Input to DYNMOD
1. General Information
The input description to the DYNMOD
module is divided into 5 sections,
each section describing one datasection referred to as AE.

Data Group A: Control Information

Data Group B: Free Vibration Analysis

Data Group C: Regular Wave, Time Domain Analysis

Data Group D: Irregular Wave, Time Domain Analysis

Data Group E: Time Domain Procedure and File Storage Parameters
Three different types of analysis are possible. Complete input for these types is shown in the list below.

Type number 1, Free vibration, requires the data sections A and B.

Type number 2, Regular wave, requires the data sections A, C and E.

Type number 3, Irregular wave, requires the data sections A, D and E.
2. Data Group A: Control Information
This datagroup is mandatory for all types of analysis with DYNMOD
.
The prescribed sequence must be followed.
2.1. Principal run parameters
2.1.1. Data group identifier, one input line
DYNMod CONTrol INFOrmation CHVERS

CHVERS: character(8)
: RIFLEX input file version, e.g. 3.2
2.1.2. Heading, three input lines

Heading, line no 1

Heading, line no 2

Heading, line no 3
Identification of the run by alphanumerical text
Always three input lines which may all be blank. Each line may contain up to 60 characters
2.1.3. Options and identifiers, one input line
IRUNCO IANAL IDRIS IDENV IDSTAT IDIRR IDRES

IRUNCO: character(4), default: DATA
: Code for data check or executable run
= FREM
: Data generation forFREMOD

= DATA
: Data check 
= ANALysis
: Analysis


IANAL: character(4)
: Type of analysis to be performed
= EIGEn
: Eigenvalue analysis.
Data section B must be given


= REGUlar
: Regular wave, time domain analysis.
Data sections C and E must be given.


= IRREgular
: Irregular wave, time domain analysis.
Data sections D and E must be given.



IDRIS: character(6)
: Data set identifier corresponding to data for one riser system established byINPMOD
and followed by a static analysis. See INPMOD: Data Group B: Single Riser Data and STAMOD: Options and print switches. 
IDENV: character(6)
: Environment identifier, corresponding to data for one environment on file established byINPMOD
. See datagroup INPMOD: Identification of the environment of input description forINPMOD
.
Reference to actual wave case is given in a later datagroup

Dummy for
IRUNCO=DATAcheck


IDSTAT: character(6)
: Static condition identifier, corresponding to data on file established bySTAMOD
. See STAMOD: Principal run parameters of input description forSTAMOD
. 
IDIRR: character(6)
: Data set identifier for irregular wave and motion data, either established by a previous run or used as reference to results stored on file by this run. 
IDRES: character(6)
: Data set identifier for this run, used as reference to results stored on files
2.2. Static load condition
For special purposes it may be convenient to change applied static loads
at the start of dynamic analysis. This option should be used with care!
One useful application is for analysing free vibration after scaling a
static nodal force to zero (SCALSF=0.0
).
Note that some static loads are applied and some modelling features are activated in dynamic analysis even if they were not applied nor activated in static analysis. See also Note: Static Analysis with Fixed Parameters and Parameter Variation.
2.2.2. Scaling parameters, one line
SCALVF SCALSF SCALCF

SCALVF: real, default: 1
: Scaling of volume forces. Dummy
not implemented in present version


SCALSF: real, default: 1
: Scaling of specified (nodal) forces 
SCALCF: real, default: 1
: Scaling of current velocities. Dummy
not implemented in present version

All forces are scaled simultaneously as
\(\mathrm {F_s=SCALiF\times F_s^0}\) Only SCALSF
is active
in the present version of the program.
2.3. Random number generator
In version 4.18 and later, the algorithm for generating pseudorandom
numbers may be selected by the user. The mersenne twister
is the
recommended method and should be used unless backwards compatibility
with previous versions is required. Note that the default value may
change in a future release. The choice of random number generator will
apply to:

generation of irregular wave time series

initial phase angles for time domain VIV loads specified for crosssections in INPMOD

generation of phase angles for application of harmonic loads from a VIVANA frequency domain analysis.
It has been identified that the legacy method can give nongaussian and nonstationary wave elevation in SIMO for short crested waves with more than about 3050 discrete directions, depending on wave spectrum and simulation duration. By choosing the mersenne twister, these issues are avoided.
For coupled analysis, wave time series will be generated using the random number generator specified in SIMA.
2.3.2. Random number generator input, one line
CHRAN ISEED

CHRAN: character (7), default: TWISTER
: Choice of random number generator
= 'LEGACY'
: Legacy random number generator used. Results will be consistent with previous RIFLEX versions. 
= 'TWISTER'
: Mersenne Twister’ random number generator used. Results will NOT be consistent with previous RIFLEX versions.


ISEED: integer, default: 7
: Starting parameter of random number generator for use when input of starting value is not available; e.g. time domain VIV loads. Currently not used.
3. Data Group B: Free Vibration Analysis
This datagroup is given if and only if IANAL=EIGEn
, see
Options and indetifier, one input line.
3.1. Free vibration options
3.1.2. Number of eigenvalues and eigenvectors, one input line
NEIG

NEIG: integer
: Number of eigenvalues and eigenvectors to be calculated.
3.1.3. Computation parameters, one input line
The parameters below correspond to Lanczos’ method for solution of eigenvalue problems. For a detailed discussion, see B. NourOmid, B.N. Parlett, R.L. Taylor: Lanczos versus Subspace Iteration for Solution of Eigenvalue Problems, International Journal for Numerical Methods in Engineering, Vol. 19, pp. 859871, 1983. or B.N. Parlett: The Symmetric Eigenvalue Problem, PrenticeHall, 1980.
TOL MAXLAN

TOL: real >0, default: 1.0e10
: Maximum acceptable relative error in computed eigenvalues 
MAXLAN: integer, default: 8+2*NEIG
: Maximum number of Lanczos steps (vectors) to be used. Note that if specifiedMAXLAN >= 8+2*NEIG
3.2. Print options for results
3.2.2. Print selection parameters, one input line
This parameter is introduced to avoid very large dublicated amounts of result data to ASCII file
IPRES

IPRES: integer, default: 0
: Print switch for eigenvectors on ASCII file<prefix>_dynmod.res
/<prefix>_eigmod.res
files.
IPRES = 0
: No print of eigenvector on ASCII file 
IPRES = 1
: Print of eigenvectors on ASCII file 
IPRES = 2
: Debug print from the eigenvalue solver in addition to print of eigenvectors on ASCII file

4. Data Group C: Regular Wave, Time Domain Analysis
This data group is given for IANAL = REGUlar
, see
Options and identifiers, one input line. Datagroup A and E must also be given
for complete definition of a regular time domain analysis.
4.1. Parameters for definition of analysis and further input
4.1.2. Analysis parameters, one input line
NPER NSTPPR IRWCN IMOTD

NPER: integer
: Number of periods for regular wave analysis, referring to wave or motion periods (of first vessel) 
NSTPPR: integer, default: 80
: Number of integration time steps per period, recommended value: 50120 
IRWCN: integer
: Wave parameter
IRWCN = 0
: No wave acting, motions must be present 
IRWCN = N
: Wave acting. Regular wave case N on actual environment used in present analysis 
If no waves are acting, the period for harmonic motions is specified in Motion amplitudes of support vessel, one input line


IMOTD: integer
: Platform motion parameter
IMOTD = 0
: No motions, waves must be present 
IMOTD = 1
: Platform motion generated on the basis of wave data (wave period and amplitude) and motion transfer functions. Reference to transfer functions given in Options and identifiers, one input line. 
IMOTD = 2
: Platform motions specified in Regular vessel motion

The platform motions are independent of the wave loading parameters given in Load modelling, regular waves.
Extreme values of response parameters from last integration period will normally be stored on file (cfr. File storage of displacement response). In addition, displacement histories from selected nodes and force and curvature histories from selected elements can be stored if wanted. Specification of such data storage is given in data groups File storage of displacement response, File storage for internal force and File storage of curvature response.
4.2. Load modelling, regular waves
This data group is given if IRWCN >= 1
(data group
Analysis parameters, one input line above).
4.2.2. Method for wave load calculation, one input line
IWTYP ISURF IUPPOS

IWTYP: integer, default: 1
: Wave theory parameter
IWTYP = 1
: Airy linear wave theory 
IWTYP = 2
: Stoke 5th order wave theory


ISURF: integer, default: 1
: Sea surface definition, see the figureDefinition of sea surface
below.
Dummy if
IWTYP = 2

ISURF = 1
: Integration of wave forces to mean water level 
ISURF = 2
: Integration of wave forces to wave surface, deformation of potential by stretching and compression 
ISURF = 3
: Integration of wave forces to wave surface, move of potential to actual surface 
ISURF = 4
: Integration of wave forces to wave surface by keeping the potential constant from mean water level to wave surface


IUPPOS: integer, default: 2
: Riser position parameter
IUPPOS = 0
: as 1, but the riser is kept fixed in static position, for computation of surface penetrating element. I.e. a node that is wet or dry at the end of the static analysis will continue to be considered wet or dry with regards to kinematics in the dynamic simulation. Recommended only for comparison with linear methods. 
IUPPOS = 1
: Wave induced velocities and accelerations calculated at static riser position 
IUPPOS = 2
: Wave induced velocities and accelerations calculated at updated (dynamic) positions

Note: The option IUPPOS = 0
cannot be combined with linear analysis,
ITDMET = 1
, or nonlinear analysis, ITDMET = 2
and SIMO
bodies.
4.3. Regular vessel motion
This data group is given only if IMOTD=2
(see input group
Analysis parameters, one input line).
4.3.2. Definition of vessel motion, two lines for each vessel
Motion amplitudes of support vessel
and Motion phase angles
must be
given for all NVES
vessels in systems (totally 2x`NVES` lines).
Motion amplitudes of support vessel, one input line
Forced displacements are specified for the support vessel. Forced displacements for the terminal points are found by transformations.
XAMP YAMP ZAMP XRAMP YRAMP ZRAMP PER

XAMP: real
: Motion amplitude, global xdirection \(\mathrm {[L]}\) 
YAMP: real
: Motion amplitude, global ydirection \(\mathrm {[L]}\) 
ZAMP: real
: Motion amplitude, global zdirection \(\mathrm {[L]}\) 
XRAMP: real
: Motion amplitude, global xrotation \(\mathrm {[degrees]}\) 
YRAMP: real
: Motion amplitude, global yrotation \(\mathrm {[degrees]}\) 
ZRAMP: real
: Motion amplitude, global zrotation \(\mathrm {[degrees]}\) 
PER: real
: Period of motion \(\mathrm {[T]}\)
PER
is dummy input if a regular wave is specified, i.e. IRWCN > 0
(data group Analysis parameters).
In the case of multiple vessels, PER
is only read for the first vessel
and the specified period used for all vessels.
Motion phase angles, one input line
XPHA YPHA ZPHA XRPHA YRPHA ZRPHA

XPHA: real
: Phase angle, xmotion \(\mathrm {[degrees]}\) 
YPHA: real
: Phase angle, ymotion \(\mathrm {[degrees]}\) 
ZPHA: real
: Phase angle, zmotion \(\mathrm {[degrees]}\) 
XRPHA: real
: Phase angle, xrotation \(\mathrm {[degrees]}\) 
YRPHA: real
: Phase angle, yrotation \(\mathrm {[degrees]}\) 
ZRPHA: real
: Phase angle, zrotation \(\mathrm {[degrees]}\)
All phase angles are defined as follows:
Positive angle: Forward phase shift; motion before sea surface at global origin.
Surface: \(\mathrm {\eta =\eta _asin(\omega t+\phi _p),\quad \phi _p=kxcos(\beta )kysin(\beta )}\)
Motion: \(\mathrm {x_i=x_{ai}sin(\omega t+\phi _i)}\)
Where:

\(\mathrm {x_i}\) is equation of motion

\(\mathrm {\eta _a}\) is wave amplitude

\(\mathrm {x_{ai}}\) is motion amplitude
XAMP
,YAMP
, etc. 
\(\mathrm {\phi _i}\) is phase angle,
XPHA
,YPHA
, etc. 
\(\mathrm {k}\) is wave number

\(\mathrm {\omega }\) is angular frequency

\(\mathrm {x,y}\) is global coordinates
If the forward phase shift \(\mathrm {\phi _i^{xy}}\) between
wave and motion at the same point (x,y) is known, the phase into
RIFLEX
must be modified as follows:
\(\mathrm {\phi _i=\phi _i^{xy}+\phi _p}\)
in order to obtain phase relation between motion at (x,y) and a wave with start at global origin as defined above.
5. Data Group D: Irregular Wave, Time Domain Analysis
This data group is given for IANAL=IRREgular
, see
Options and identifiers, one input line. Data group A and E must also be given
for complete definition of an irregular time domain analysis.
5.1. Irregular time series parameters
The input in this data group is used to specify the method used for computation of the underlaying irregular waves, i.e. the seed used for random number generation and the frequency resolution.
The data group may be skipped if default values are wanted. The data
group is dummy if any floater force models are present in the model.
(The analysis is done in combination with SIMO
, socalled coupled
analysis, and the irregular time series parameters defined by input to
SIMO
).
5.1.2. Parameters, one input line
IRAND TIMGEN DTGEN CHFREQ CHAMP

IRAND: integer, default: 1
: Starting parameter of random number generator 
TIMGEN: real, defaul: 16384
: Length of prescribed wave and motion time series \(\mathrm {[T]}\) 
DTGEN: real, defaul: 0.5
: Time increment of presampled time series \(\mathrm {[T]}\) 
CHFREQ: character(4), default: FFT
: Option for selecting wave frequency components
= 'FFT'
: Wave frequency components are selected among the FFT frequencies given byTIMEGEN
andDTGEN
. The default criteria are used to find the first and last frequencies.


CHAMP: character(5), default: DET
: Option for selecting wave component amplitudes
= 'DET'
: Deterministic wave amplitudes are used. 
= 'STOCH'
: Stochastic wave amplitudes are used. 
= 0
: Interpreted asDET
. Included for compatibility with earlier versions.

Note that this data group is dummy for coupled analysis.
Also note that:

TIMGEN
should be equal or longer than the simulation length,TIME
, given in Irregular response analysis and subsequent input. 
TIMGEN
will, if necessary, be increased to give a power of 2 time steps (DTGEN
). 
The actual time increment used for time domain analysis is defined by the parameter
DT
, see Irregular response analysis and subsequent input. 
To represent the wave surface and motion time series properly, time increments,
DTGEN
, in the range 0.51 s are normally acceptable.
Time series of wave elevation are generated from the wave spectrum for simulations with irregular waves. Different wave seeds will result in different wave time series. The wave time series are realizations of the wave process described by the wave spectrum.
With deterministic amplitudes, the amplitude pf each wave component is given directly by the wave spectrum and will be the same for all realizations. The phase angles of the different wave components will vary between realizations, resulting in different wave time series. The wave time series will all have the same spectrum, identical to the original wave spectrum at the frequencies of the wave components.
With stochastic amplitudes, the amplitude for each wave component will also be varied around the value of the wave spectrum. The spectra of the generated wave time series will vary between realizations and will not be the same as the original wave spectrum. Using stochastic amplitudes will normally give more variation between the results for different wave seeds.
5.2. Irregular response analysis and subsequent input
5.2.2. Analysis parameters, one input line
IRCNO TIME DT CHWAV CHMOT CHLFM TBEG ISCALE

IRCNO: integer/character
: Irregular wave case number in actual environment applied in this run. Dummy for coupled analysis.
IRCNO = FILE
orIRCNO = 1
: Wave time series read from file. Data groups Irregular waves and Wave time series file must be given


TIME: real, default: 11000
: Length of simulation \(\mathrm {[T]}\) 
DT: real, default: 0.1
: Time step \(\mathrm {[T]}\)
See below


CHWAV: character(4), default: NEW
: Irregular wave indicator
= 'NONE'
: No wave forces in present analysis. If specified the riser will have forced excitation at upper end and oscillate in undisturbed water or in constant current 
= NEW
: Wave forces present. New data generated. Data group Irregular waves must be given.


CHMOT: character(4), default: STAT
: Irregular motion indicator
= 'NONE'
: No irregular motions in present analysis 
= STAT
: Forced irregular motions present. Computation of prescribed motions will be based on vessel position in final static position. 
= NEW
: Interpreted asCHMOT=STAT

= FILE
: Forced irregular motions present. Wave frequency motion time series read from file. Data group Wave frequency motion time series file must be given.


CHLFM: character(4), default: 'NONE'
: Low frequency motion indicator
= 'NONE'
: No low frequency irregular motions present 
= FILE
: Forced low frequency irregular motions present. Low frequency motion time series read from file. Data group Low frequency motion time series file must be given.


TBEG: real, default: 0
: Time in wave and motion time series that dynamic simulation will start from \(\mathrm {[T]}\) 
ISCALE: integer, default: 0
: Switch for scaling of terminal point motions
ISCALE = 0
: No scaling 
ISCALE = 1
: Scaling: Input line Support vessel motion scaling factors has to be given.

DT
will be adjusted to get an integer ratio between DTGEN
and DT
.
DT
given as negative integer defines the ratio between time step used
in presimulation of waves and/or WFmotions and the time step to be
used in the time simulation. (DTGEN/DT >= 1
)
TBEG
allows for arbitrary start point in the pregenerated time
series. If the end of the time series is reached during dynamic
integration, a warning is written and motions and water kinematics will
be taken from the start. This can also be useful for elimination of
transients from the time series statistics.
An irregular analysis without waves or vessel motions may be run by
specifying CHWAV = 'NONE'
, CHMOT = 'NONE'
and CHLFM = 'NONE'
.
IRCNO
must still reference a legal irregular wave case, but the wave
will not be used as no wave kinematics will be generated and not vessel
motions be applied.
5.2.3. Support vessel motion scaling factors. Only given for ISCALE=1. One line for each vessel in system (NVES lines)
SCALX SCALY SCALZ SCALXR SCALYR SCALZR

SCALX: real, default: 1
: Scaling for global Xmotion \(\mathrm {[1]}\) 
SCALY: real, default: 1
: Scaling for global Ymotion \(\mathrm {[1]}\) 
SCALZ: real, default: 1
: Scaling for global Zmotion \(\mathrm {[1]}\) 
SCALXR: real, default: 1
: Scaling for global Xrotation \(\mathrm {[1]}\) 
SCALYR: real, default: 1
: Scaling for global Yrotation \(\mathrm {[1]}\) 
SCALZR: real, default: 1
: Scaling for global Zrotation \(\mathrm {[1]}\)
The motions are scaled directly as \(\mathrm {DISP_i=SCAL_i\times Motion_i}\) where \(\mathrm {Motion_i}\) is the precomputed motion quantity \(\mathrm {_i}\).
5.3. Irregular waves
This data group is omitted for CHWAV='NONE'
, see data group
Analysis parameters, one input line.
The data group also controls the method for computation of wave
kinematics and motions of the support vessels. In this context FFT or
FFT and cosine series combined means that the vessel motion is
pregenerated by means of FFT, while the wave kinematics are either
pregenerated (FFT) or computed during the actual simulation by use of
cosine series. Cosine series only
means that both vessel motion and
wave kinematics are computed based on cosine series. It is possible to
overrule the cosine series application for wave kinematics for parts of
the the system by specifying FFT in the detailed specifications, see
Additional detailed specification of wave kinematics points (optional). (FFT
or FFT and
cosine series combined only
.)
5.3.2. Procedure for wave force calculation, one input line
IUPPOS ISURF KINOFF CHSTEP NODSTP ZLOWER ZUPPER IOPDIF IOPWKI

IUPPOS: integer, default: 1
: Position for calculation of irregular wave kinematics
= 1
: Kinematics at static positions 
= 2
: Kinematics at instantaneous positions calculated by summation of cosine components. 
= 2
: Kinematics at static positions calculated by summation of cosine components. This option is mainly useful for testing. 
= 0
: As 1 but riser fixed in static position, (wet
elements alsowet
dynamic)


ISURF: integer, default: 1
: Code for kinematics in wave zone
= 1
: Integration of wave forces to mean water level 
= 2
: Integration of wave forces to wave surface by stretching and compression of the wave potential 
= 3
: Integration of wave forces to wave surface by moving the potential to actual surface 
= 4
: Integration of wave forces to wave surface by keeping the potential constant from mean water level to wave surface 
= 5
: 2nd order wave (integration of wave forces to wave surface)
The formulation for 2nd order wave kinematics is based on the Stoke 2nd order wave theory. Only available for kinematics calculated at static position;
IUPPOS = 1
orIUPPOS = 0
.



KINOFF: integer, default: 0
: Code for default kinematics points procedure
= 0
: Default procedure on. The initial selection of positions for computation of kinematics is determined by the parametersNODSTP
,ZLOWER
andZUPPER
for all lines in the system. Subsequent specification (see Additional detailed specification of wave kinematics points (optional)) will replace the initial selection. 
= 1
: Default procedure off. Kinematics will only be computed at positions given by subsequent specification (see Additional detailed specification of wave kinematics points (optional))


CHSTEP: character(4)
: Code for interpretation of the next parameter
= NODE
: Next parameter interpreted asNODSTP


NODSTP: integer
: Node step for calculating wave kinematics. (Dummy forKINOFF = 1
)
Kinematics calculated for every
NODSTP
node betweenZLOWER
andZUPPER
(see Definition of NODSTP, ZLOWER and ZUPPER). 
For intermediate nodes kinematics are derived by linear interpolation.

Wave kinematics will always be calculated at submerged supernodes.

Note that a negative value of
NODSTP
may be given. The distance betweenZUPPER
andZLOWER
is then divided into 4 (equal) intervals andNODSTP
is increased fromABS(NODSTP)
in the upper interval via2xABS(NODSTP)
in the next interval and4xABS(NODSTP
) to8xABS(NODSTP)
in the two lower intervals, see Definition of NODSTP, ZLOWER and ZUPPER.


ZLOWER: real, default: WDEPTH
: Zcoordinate indicating lowest node position for which wave kinematics are calculated \(\mathrm {[L]}\)
Dummy for
KINOFF = 1

For
WDEPTH
, see INPMOD: Water depth and wave indicator

ZUPPER: real, default: 4 x STD_WA
: Upper limit for wave kinematics \(\mathrm {[L]}\)
Dummy for
KINOFF = 1

STD_WA
is the standard deviation of the total wave elevation


IOPDIF: integer, default: 0
: Option for specification of wave kinematic transfer function.
IOPDIF = 0
: No transfer function to be specified 
IOPDIF = 1
: Read transfer functions from the file specified in Wave kinematics transfer function file name (below).


IOPWKI: integer, default: 0
: Option for specification of wave kinematic time series.
IOPWKI = 0
: No wave kinematics time series to be specified 
IOPWKI = 2
: Read wave kinematics time series from the binary file specified in Wave kinematics transfer function file name (below).

NODSTP
, ZLOWER
and ZUPPER
will normally be sufficient for
specifying the selection of wave kinematics points.
Note that for large or complicated systems
Additional detailed specification of wave kinematics points (optional) may be used to
override the selection given by NODSTP
, ZLOWER
and ZUPPER
; e.g.
skip generation of wave kinematics for selected lines, generate
kinematics at more points along an important line.
Note that the definition of ISURF is also used to determine where to apply wind forces to airfoil cross sections near the water line. That is, no wind forces are applied to wet sections of the element. The wind speed is nevertheless taken to be zero at or below the mean water level.
Note that the option IUPPOS = 0
cannot be combined with linear
analysis, ITDMET = 1
, or nonlinear analysis, ITDMET = 2
and SIMO
bodies.
Wave kinematics transfer function file name
This data group is omitted for IOPDIF = 0
CHFDIF

CHFDIF: character(80)
: File name with wave kinematic transfer function.
The file format is described in Diffracted Wave Transfer Functions at Points.

Wave kinematics time series file name
This data group is omitted for IOPWKI = 0
Wave kinematics read from file will replace the corresponding wave
kinematics calculated by DYNMOD
. These kinematics will then be used in
the calculation of Morison type hydrodynamic loads on RIFLEX
elements.
Loads on SIMO
bodies will NOT be affected.
RIFLEX
vessel motions based on vessel motion transfer functions and
MacCamy Fuchs and Potential flow loads on RIFLEX
elements are
pergenerated from the wave Fourier components and are therefore NOT
affected by the wave kinematics read from file. Elements with MacCamy
Fuchs or Potential flow loads may not have kinematics read from file.
If kinematics read from file are used in a simulation with SIMO
bodies, vessel motions based on vessel motion transfer functions or
pregenerated hydrodynamic loads, the user must ensure that the
kinematics are consistent with the Fourier components.
CHFWKI

CHFWKI: character(80)
: File name with wave kinematic time series.
The file format is specified by
IOPWKI
and is the same as the kinematics file with the same format exported from DYNMOD using Storage of irregular wave kinematics

ICOLMX ICOLTM NQNTWK

ICOLMX: integer, default: 0
: Maximum number of columns on file. For binary format,IOPWKI = 2
, this includes the two columns of FORTRAN specific data, one column for time andNQNTWK
columns for each node for which kinematics are stored on this file; i.e. 3 +NQNTWK
* n. Please see the key filekey_<prefix>_wavkin.txt
generated when storing kinematics. 
ICOLTM: integer, default: 2
: Column number on file for time 
NQNTWK
: integer, default: 0`: Number of kinematics quantities on the file for each kinematic node.
NQNTWK =7
: Wave elevation, xvelocity, yvelocity, zvelocity, xacceleration, yacceleration and zacceleration are read for each specified node 
NQNTWK = 8
: Wave elevation, xvelocity, yvelocity, zvelocity, xacceleration, yacceleration, zacceleration and dynamic pressure are read for each specified node 
NQNTWK =0
: The value of NQUANT will be found from the specified column numbers.

Additional detailed specification of wave kinematics points (optional)
As many input lines as needed. Note three alternative formats.
For wave kinematics calculated by the program from the undisturbed waves.
LINEID CHSTEP = NODE NODSTP

LINEID: character(8)
: Line identifier 
CHSTEP: character(4)
:= Node

NODSTP: integer
: Node step for calculating wave kinematics
= 0
: No kinematics for this line 
> 0
: Kinematics for eachNODSTP
node

For wave kinematics given by wave kinematics transfer functions (diffracted waves)
LINEID CHSTEP= DIFF ILSEG ILNODE IVES PTNOUS

LINEID: character(8)
: Line identifier 
CHSTEP: character(4)
:= DIFF

ILSEG: integer
: Local segment number within line LINEID 
ILNODE: integer
: Local node number within ILSEG 
IVES: integer
:
= 0
: Use undisturbed wave kinematics at this node 
> 0
: Support vessel number. Used as reference to transfer function for diffracted wave kinematics.


PTNOUS: integer
: Point reference(s) to transfer function for diffracted wave kinematics
Up to 30 values of PTNOUS may be given for a node. The diffracted kinematics at the specified node will be generated by interpolation based on the nearest point references.
For wave kinematics given by wave kinematics time series
LINEID CHSTEP= WKFI ILSEG ILNODE ICOLST

LINEID: character(8)
: Line identifier 
CHSTEP: character(4)
:= WKFI

ILSEG: integer
: Local segment number within line LINEID 
ILNODE: integer
: Local node number within ILSEG 
ICOLST: integer
: Column number for the first wave kinematics time series for this node
5.4. Wave and motion time series files
5.4.1. Wave time series file
This data group is given only if IRCNO = FILE
.
Wave time series file information
CHFTSF IFORM ICOTIM ICOWAV

CHFTSF: character(60)
: File name 
IFORM: integer, default: 1
: File format code
= ASCI
: Column organised ASCII file 
= STAR
: Startimes file


ICOTIM: integer, default: 1
: Column number for time
Dummy for
IFORM = STAR


ICOWAV: integer/real, default: 2
: Column or time series number for wave elevation
The wave direction is given by the parameter WADR1
given in INPMOD
for the irregular wave case IRCNO
referred to in
Analysis parameters, one input line..
ICOTIM
and ICOWAV
will refer to columns on an ASCII file;
e.g. ICOTIM=1
and ICOWAV=2
if the time and wave elevation are in the
first and second columns; or to a time series number on a Startimes
file; e.g. ICOWAV=10.01
for time series 10, version 1.
An arbitrary time step may be used on an ASCII file, while the Startimes file has a fixed step. Linear interpolation is used to get the motions at the time step (DTWF)
Direction, location of measurement and cutoff for filtering
WAVDIR XGWAV YGWAV TMIN TMAX

WAVDIR: real, default: 0
: Wave direction \(\mathrm {[deg]}\) 
XGWAV: real, default: 0
: Global xcoordinate for position where time series is measured 
YGWAV: real, default: 0
: Global ycoordinate for position where time series is measured 
TMIN: real, default: 0
: Period corresponding to cutoff frequency for filtering 
TMAX: real, default: 0
: Period corresponding to cutoff frequency for filtering
If TMIN
and TMAX
are both zero: No filtering
If TMIN
and TMAX
are both different from zero: bandpass filtering
Filtering is not implemented in present version
5.4.2. Wave frequency motion time series file
This data group is given only if CHMOT=FILE
. Note that data must be
given for all vessels in the system.
Wave frequency motions file information, NVES input lines
IVES CHFTSF IFORM IKIND IROT ICOTIM ICOXG ICOYG ICOZG ICOXGR ICOYGR ICOZGR

IVES: integer
: Vessel Number 
CHFTSF: character(60)
: File name 
IFORM: character(4), default: ASCI
: File format code
= ASCI
: Column organised ASCII file 
= STAR
: Startimes file 
= NONE
: No wave frequency motions for this vessel. The remainder of this input line is dummy


IKIND: character(4), default: POSI
: Kind of motion time series input
= POSI
: Global positions, i.e. global coordinates. The rotations are applied in the Euler sequence: RzRyRx. Consistent with vessel motion time series fromSIMO
. 
= DYND
: Global dynamic displacements; i.e. global coordinates minus the final static position. The rotations are applied in the Euler sequence: RxRyRz


IROT: character(4), default: DEGR
: Unit of rotations
= DEGR
: Rotations given in degrees 
= RADI
: Rotations given in radians


ICOTIM: integer, default: 1
: Column number for time
Dummy for
IFORM = STAR


ICOXG: integer/real, default: 0
: Column or time series number for specification of global xmotion. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
. 
ICOYG: integer/real, default: 0
: Column or time series number for specification of global ymotion. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
. 
ICOZG: integer/real, default: 0
: Column or time series number for specification of global zmotion. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
. 
ICOXGR: integer/real, default: 0
: Column or time series number for specification of global xrotation. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
. 
ICOYGR: integer/real, default: 0
: Column or time series number for specification of global yrotation. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
. 
ICOZGR: integer/real, default: 0
: Column or time series number for specification of global zrotation. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
.
Dofs may be omitted by giving ICOxxx=0
ICOxxx
will refer to a column for an ASCII file; e.g. ICOX=2
if the
dynamic x motion time series is in the second column; or to a time
series number for a Startimes file, e.g. ICOX=1.02
for time series 1,
version 2.
An arbitrary time step may be used on an ASCII file, while the Startimes
file has a fixed time step. Linear interpolation is used to get the
motions at the time step (DTWF
).
Translational dofs are given in length units. Rotational dofs are given
in degrees or radians, depending on the option IROT
.
If only one rotation is nonzero or if all rotations are small, the order in which the rotations are applied will not be significant.
Please note that the line length of ASCII input files is currently limited to 260 characters, see Formats in How to Run the Program. Note that a RIFLEX input line may be split into several lines on the input file.
5.4.3. Low frequency motion time series file
This data group is given only if CHLFM=FILE
. Note that data must be
given for all vessels in the system.
Low frequency motions file information, NVES input lines
IVES CHFTSF IFORM IKIND IROT ICOTIM ICOXG ICOYG ICOZGR

IVES: integer
: Vessel Number 
CHFTSF: character(60)
: File name 
IFORM: character(4), default: ASCI
: File format code
= ASCI
: Column organised ASCII file 
= STAR
: Startimes file 
= NONE
: No wave frequency motions for this vessel. The remainder of this input line is dummy


IKIND: character(4), default: POSI
: Kind of motion time series input
= POSI
: Global positions, i.e. global coordinates. The rotations are applied in the Euler sequence: RzRyRx. Consistent with vessel motion time series fromSIMO
. 
= DYND
: Global dynamic displacements; i.e. global coordinates minus the final static position. The rotations are applied in the Euler sequence: RxRyRz


IROT: character(4), default: DEGR
: Unit of rotations
= DEGR
: Rotations given in degrees 
= RADI
: Rotations given in radians


ICOTIM: integer, default: 1
: Column number for time
Dummy for
IFORM = STAR


ICOXG: integer/real, default: 0
: Column or time series number for specification of global xmotion. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
. 
ICOYG: integer/real, default: 0
: Column or time series number for specification of global ymotion. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
. 
ICOZGR: integer/real, default: 0
: Column or time series number for specification of global zrotation. Absolute position ifIKIND = POSI
, relative to static position ifIKIND = DYND
.
Dofs may be omitted by given ICOxxx=0
ICOxxx
will refer to a column for an ASCII file; e.g. ICOSUR=2
if
the dynamic x motion time series is in the second column; or to a time
series number for a Startimes file, e.g. ICOX=1.02
for time series 1,
version 2.
An arbitrary time step may be used on an ASCII file, while the Startimes
file has a fixed time step. Linear interpolation is used to get the
motions at the time step (DTWF
).
Translational dofs are given in length units. Rotational dofs are given
in degrees or radians, depending on the option IROT
.
If only one rotation is nonzero or if all rotations are small, the order in which the rotations are applied will not be significant.
5.5. Print options for FFT analysis
5.5.2. Fourier print options
IPMOTI IPWAFO IPHFTS IPLFTS IPTOMO IPVEAC

IPMOTI: integer, default: 0
: Print option for the main routine
⇐ 0
: No print 
> 1
: Key information printed 
> 2
: Some more data printed 
> 5
: Low level debug print during numerical integration activated


IPWAFO: integer, default: 0
: Print option for the wave fourier component generation
Not active in present version


IPHFTS: integer, default: 0
: Print option for HFtime series generation
⇐ 0
: No print 
> 0
: Print of wave frequency vessel motion time series


IPLFTS: integer, default: 0
: Print option for LFtime series generation
⇐ 0
: No print 
> 0
: Print of low frequency vessel motion time series


IPTOMO: integer, default: 0
: Print option for TOTAL motion time series generation
⇐ 0
: No print 
> 0
: Print of total vessel motion time series


IPVEAC: integer, default: 0
: Print option for generation of water particle velocities and acceleration
⇐ 0
: No print 
> 1
: Key information printed 
> 2
: Some data printed 
> 5
: Extensive debug print of arrays with water particle velocities and accelerations

This datagroup is normally supposed to be omitted. Increasing value of print options gives increasing amount of print.
5.6. Storage of irregular wave kinematics (optional)
5.6.2. Wave kinematics storage options one input line
NLKINE IKINFM

NLKINE: integer, default: 0
: Number of specifications for storage of wave kinematics
= 0
: Wave elevation, velocities, accelerations and pressure are stored for all kinematics nodes. Currently, no other value is allowed.


IKINFM: integer, default: 2
: File format for kinematics storage
= 1
: ASCII format 
= 2
: Binary format

Pregenerated wave kinematics are written to <prefix>_wavkin.asc
or
<prefix>_wavkin.bin
. Kinematics calculated during the simulation;
IUPPOS = 2 or 2
; are written to <prefix>_updkin.asc
or
<prefix>_updkin.bin
.
The contents are described in key_<prefix>_wavkin.txt
or
key_<prefix>_updkin.txt
.
The format of the <prefix>_wavkin.bin
and <prefix>_updkin.bin
are shown in Table 1.
Table 1 shows storage of data for M
number of time steps and N
number of kinematic nodes.The data is stored row by row.
The number of columns is equal to 3+8N. The first and last columns contain the number of
bytes per line ( i.e. number of bytes = 4(8N+1) ). The second column is the time step.
The numbers are stored as 32bit (4byte) floating point number, except the first and last column which is 4 byte unsigned integer. The disk consumption is equal to 4M(3+8N) bytes.
The number of kinematics quatities in the file generated by Riflex is 8. That is the wave elevation, xvelocity, yvelocity, zvelocity, xacceleration, yacceleration, zacceleration and dynamic pressure are stored for each specified node. 
Column no=1 
2 
3 to 10 
11 to 18 
19 to 26 
… 
3+(N1)8 to 2+8N 
3+8N 
time 
Node_{1} 
Node_{2} 
Node_{3} 
… 
Node_{N} 

4(8N+1) 
t_{1} 
wave(t_{1},x_{1}) 
wave(t_{1},x_{2}) 
wave(t_{1},x_{3}) 
… 
wave(t_{1},x_{N}) 
4(8N+1) 
4(8N+1) 
t_{2} 
wave(t_{2},x_{1}) 
wave(t_{2},x_{2}) 
wave(t_{2},x_{3}) 
… 
wave(t_{2},x_{N}) 
4(8N+1) 
4(8N+1) 
t_{3} 
wave(t_{3},x_{1}) 
wave(t_{3},x_{2}) 
wave(t_{3},x_{3}) 
… 
wave(t_{3},x_{N}) 
4(8N+1) 
… 
… 
… 
… 
… 
… 
… 

4(8N+1) 
t_{M} 
wave(t_{M},x_{1}) 
wave(t_{M},x_{2}) 
wave(t_{M},x_{3}) 
… 
wave(t_{M},x_{N}) 
4(8N+1) 
A list of the kinematic nodes can be found on the <prefix>_dynmod.resfile. 
If the kinematic binary file is generated by an external tool and used as input to Riflex, Section 5.3.2.2, the number of kinematics quatities can be 7 (wave elevation, xvelocity, yvelocity, zvelocity, xacceleration, yacceleration and zacceleration). 
6. Data Group E: Time Domain Procedure and File Storage Parameters
This data group must always be given for IANAL = REGU
and IRRE
(time
domain analysis) specified in input line Options and identifiers, one input line.
6.1. Method of analysis and subsequent input
6.1.2. Method and subsequent input, one input line
ITDMET INEWIL

ITDMET: integer, default: 1
: Method indicator
ITDMET = 0
: Prestochastic analysis only. The rest of the data in input groups E are irrelevant 
ITDMET = 1
: Linear analysis 
ITDMET = 2
: Nonlinear analysis. More information to define method is given in Nonlinear step by step integration


INEWIL: integer, default: 1
: Procedure indicator
INEWIL = 1
: Newmark’s procedure 
INEWIL = 2
: Wilson’s procedure, illegal for nonlinear analysis

6.1.3. Time integration and damping parameters, one input line
This data group can be omitted if default values are wanted.
BETIN GAMMA TETHA A1 A2 A1T A1TO A1B A2T A2TO A2B DAMP_OPT

BETIN: real, default: 4/6
: Inverse value of betaparameter of the Newmark betafamily of integration operators
BETIN = 4.0
gives beta=1/4,i.e. constant average acceleration method


GAMMA: real, default: 0.5
: Value of the parameter gamma of the Newmark operators (usually equal to 0.5) 
TETHA: real, default: See below
: Value of the parameter tetha in Wilson’s integration method 
A1: real, default: 0
: Global mass proportional damping factor \(\mathrm {a_1}\), see definition below 
A2: real, default: 0.001/0
: Global stiffness proportional damping factor \(\mathrm {a_2}\) 
A1T: real, default: 0
: Additional local mass proportional damping factor \(\mathrm {a_{1t}}\) for tension 
A1TO: real, default: 0
: Additional local mass proportional damping factor \(\mathrm {a_{1to}}\) for torsion 
A1B: real, default: 0
: Additional local mass proportional damping \(\mathrm {a_{1b}}\) for bending 
A2T: real, default: 0
: Additional local stiffness proportional damping factor \(\mathrm {a_{2t}}\) for tension 
A2TO: real, default: 0
: Additional local stiffness proportional damping factor \(\mathrm {a_{2to}}\) for torsion 
A2B: real, default: 0
: Additional local stiffness proportional damping factor \(\mathrm {a_{2b}}\) for bending 
DAMP_OPT: character(4), default: TOTA
: Option for stiffness contribution to Rayleigh damping
= TOTA
: Stiffness proportional damping is applied using total stiffness, i.e. both material and geometric stiffness 
= MATE
: Stiffness proportional damping is applied using material stiffness only

Default values:

For
INEWIL=1
(Newmark) the following alternative default values are:BETIN=4.0
,THETA=1.0
,A2=0.001

For
INEWIL=2
(Wilson) default values are:BETIN=6.0
,TETHA=1.4
(linear)
Global proportional damping formulation:
\(\mathrm {\boldsymbol{\mathrm C}=a_1\boldsymbol{\mathrm M}+a_2\boldsymbol{\mathrm K}}\)
This means that the global damping matrix \(\mathrm {\boldsymbol{\mathrm C}}\) is established as a linear combination of the global mass (\(\mathrm {\boldsymbol{\mathrm M}}\)) and the total or material stiffness (\(\mathrm {\boldsymbol{\mathrm K}}\)) matrices.
The mass and stiffnessproportional damping specified here will not be applied to elements for which mass and/or stiffnessproportional damping is specified in INPMOD.
Numerical values of \(\mathrm {a_1}\) and \(\mathrm {a_2}\):
Let the structural damping to critical damping ratio,
\(\mathrm {c/(2m\omega )}\), at two natural frequencies
\(\mathrm {\omega _1}\) and \(\mathrm {\omega _2}\)
be \(\mathrm {\lambda_1}\) and
\(\mathrm {\lambda_2}\), respectively.
Then A1
and A2
can be computed as: 
\(\mathrm {a_1=\frac{2\omega _1\omega _2}{\omega _2^2\omega _1^2}(\lambda_1\omega _2\lambda_2\omega _1)}\)

\(\mathrm {a_2=\frac{2(\omega _2\lambda_2\omega _1\lambda_1)}{\omega _2^2\omega _1^2}}\)
Additional local proportional damping formulation:
In this approach, the damping coefficients are introduced in the local degrees of freedom in order to allow for different damping levels in bending, torsion and tension. The element damping matrix can the be written as
\(\mathrm {\boldsymbol{\mathrm c}=a_1\boldsymbol{\mathrm M}+a_{1t}\boldsymbol{\mathrm m}_t+a_{1to}\boldsymbol{\mathrm m}_{to}+a_{1b}\boldsymbol{\mathrm m}_b+a_2\boldsymbol{\mathrm K}+a_{2t}\boldsymbol{\mathrm k}_t+a_{2to}\boldsymbol{\mathrm k}_{to}+a_{2b}\boldsymbol{\mathrm k}_{b}}\)
where subscripts \(\mathrm {_t}\), \(\mathrm {_{to}}\) and \(\mathrm {_b}\) refer to tension, torsion and bending contributions, respectively, and the matrices \(\boldsymbol{\mathrm c_{}}\), \(\boldsymbol{\mathrm m}\) and \(\boldsymbol{\mathrm k_{}}\) are local element matrices; e.g. \(\mathrm {\boldsymbol{\mathrm k}_b}\) includes all bending deformation terms in the local element stiffness matrix.
For cross sections applied for blades of a operating wind turbine the matrix \(\boldsymbol{\mathrm k_{}}\) should only include the material stiffness matrix. The geometric stiffness matrix should not be included as this would introduce damping of the rigid body motion.
One should be careful with global mass proportional damping as this may introduce internal damping from rigid body motion.
If \(\mathrm {a_1=}\) 0
, \(\mathrm {a_2}\) simply
becomes \(\mathrm {2\lambda/\omega }\).
Note that proportional damping (global and local) adds to a possible structural damping arising from hysteresis in bending moment/curvature relation.
6.1.4. Nonlinear force model, one input line. Always submit for linear and nonlinear analysis
INDINT INDHYD MAXHIT EPSHYD TRAMP INDREL ICONRE ISTEPR LDAMP

INDINT: integer, default: 1
: Indicator for modelling forces from internal slug flow
Nonlinear analysis only.

INDINT = 1
: Forces from internal slug flow not considered 
INDINT = 2
: Forces from internal slug flow considered. 
Data group Slug force calculations or Import of internal flow data from file must be given.


INDHYD: integer, default: 1
: Indicator for hydrodynamic force model. Linear analysis only. (seeDynamic Time Domain Analysis
in the Theory Manual).
INDHYD = 1
: No force iteration, use of displacements and velocities at previous time step 
INDHYD = 2
: No force iteration, use of displacements, velocities and accelerations at previous time step (not recommended) 
INDHYD = 3
: Force iteration performed


MAXHIT: integer, default: 5
: Maximum number of load iterations. Linear analysis only.
A negative value gives print of convergence for each step, then
MAXHIT = ABS(MAXHIT)


EPSHYD: real, default: 0.01
: Convergence control parameter for force iteration. Linear analysis only.
Dummy for
INDHYD = 1, 2
\(\mathrm {[1]}\)


TRAMP: real, default: 10
: Duration of startup procedure \(\mathrm {[T]}\) 
INDREL: integer, default: 0
: Indicator for rupture/release
INDREL = 0
: No riser rupture/release 
INDREL = 1
: Riser rupture/release will be simulated


ICONRE: integer, default: 0
: Ball joint connector no. to be released
ICONRE = 0
: All ball joint connectors in the system are released simultaneously 
ICONRE = i
: Ball joint connector no. i is released. See reference number ("ref no") in the table Components on theSTAMOD
result file for connector numbering. The connectors are normally numbered from the first end as 1, 2 etc. following theFEM
model.


ISTEPR: integer, default: 0
: Time step no. for release (nonlinear analysis only)
In linear analysis the ball joint connector will be released at the first step


LDAMP: integer, default: 0
: Option for calculation of proportional damping matrix in nonlinear analysis.
Irrelevant for linear analyses

LDAMP = 0
: Use constant proportional damping matrix calculated at static position 
LDAMP = 1
: Use updated proportional damping matrix according to instantaneous mass and stiffness matrices

For nonlinear analysis (ITDMET = 2
, see Method and subsequent input, one input line)
INDHYD
can have the values 1 or 2. Input of 3 will be interpreted as
2. Load iteration for nonlinear analysis will always be performed in
connection with equilibrium iteration, but not during equilibrium
correction.
If load convergence is not obtained after MAXHIT
iteration,
computation will proceed after output of warning.
As a release/rupture analysis is very sensitive, a short time step and rather firm convergence limit is required. If the response of part of the system is not of interest after the release, the Boundary change option may be used to fix the nodes in this part of the system.
6.2. Nonlinear step by step integration
This data group is only given for ITDMET=2
(input group
Method and subsequent input, one input line).).
6.2.2. Specification of incrementation procedure, one input line
ITFREQ ISOLIT MAXIT DACCU ICOCOD IVARST ITSTAT CHNORM EACCU

ITFREQ: integer, default: 1
: Frequency of equilibrium iteration
ITFREQ ⇐ 0
: Iteration will not be performed 
ITFREQ >= 1
: Iteration will be performed everyITFREQ
time step. For steps without iteration equilibrium correction will be performed. 
The remaining variables in this input line are dummy if
ITFREQ ⇐ 0


ISOLIT: integer, default: 1
: Type of iteration if iteration is to be performed
ISOLIT = 1
: True NewtonRaphson, updating of geometric stiffness from axial force 
ISOLIT = 2
: Modified NewtonRaphson iteration 
Modified NewtonRaphson iteration is not included in the current version of the program


MAXIT: integer, default: 10
: Maximum number of iterations for steps with iteration 
DACCU: real, default:
\(\mathrm {10^{6}}\): Desired accuracy for equilibrium iteration measured by a modified Euclidean displacement norm (norm of squared translations)
Recommended values: \(\mathrm {10^{6}10^{5}}\) cfr.
STAMOD
analysis \(\mathrm {[1]}\)


ICOCOD: integer, default: 1
: Code for continuation after iteration
ICOCOD = 0
: Computations interrupted if accuracy requirements are not fulfilled 
ICOCOD = 1
: Computations continue even if accuracy requirements are not fulfilled. Warning is printed


IVARST: integer, default: 0
: Code for automatic subdivision of time step
IVARST = 0
: No subdivision 
IVARST > 0
: Automatic subdivision of time step if required accuracy is not obtained with original time step or if incremental rotations are to large. 
Maximum number of subdivisions: \(\mathrm {2^{IVARST}}\)


ISTAT: integer, default: 1
: Code for time integration information
ITSTAT = 0
: No information 
ITSTAT > 1
: Number of iterations, subdivisions and obtained accuracy are presented


CHNORM: character(4), default: DISP
: Convergence norm switch
= DISP
: Use the default Euclidean displacement norm only 
= BOTH
: Use both the default Euclidean displacement norm and the energy norm


EACCU: real, default:
\(\mathrm {10^{6}}\): Required accuracy measured by energy norm
Dummy if
CHNORM=DISP

6.3. Modification to water kinematics
Modification to water kinematics due to moonpool kinematics may be specified. The water kinematics will be based on the velocities and acceleration of the actual support vessel or floater force model specified.
6.3.2. Rigid moonpool column, one input line
RIGId MOONpool COLumn
Specification of number of moonpools, one input line
NLSPEC

NLSPEC: integer
: Number of Rigid Moonpool Columns
Specification of support vessel moonpool, one input line.
CHSUPP IVES ZLLOW ZLUP

CHSUPP: character
: Type of support vessel
= VESSEL
:RIFLEX
support vessel (Prescribed motions) 
= FLOATER
: Floater force model


IVES: integer
: Support vessel number 
ZLLOW: real
: Lower Z limit (local vessel system) \(\mathrm {[L]}\) 
ZLUP: real
: Upper Z limit (local vessel system) \(\mathrm {[L]}\)
One input line
Specification of lines within present moonpool, one input line
LINEID1 LINEID2 ....... LINEIDi .........LINEIDn

LINEID: character(8)
: Line identifiers within moon pool
The data groups Specification of support vessel moonpool
and
Specification of lines within present moonpool
are to be repeated NLSPEC
times.

Rigid moonpool column may not be combined with CHMOT=
NONE
: No irregular motions, for irregular wave analysis . 
Rigid moonpool column may not be combined with IMOTD = 0: No motions, for regular wave analysis.

If current is loaded in static analysis, the current forces will be removed at start of dynamic analysis for lines within moonpool and may create a transient.
6.4. Slug force calculations
This data group is only given for INDINT=2
(see Nonlinear force model).
Note that slug forces can only be specified for single risers.
6.4.1. Data group identifier, one input line
Restrictions

The main riser line has to be modelled by beam elements

Consistent formulation (Lumped mass option is prohibited)
Assumptions

The total slug mass is constant, \(\boldsymbol{\mathrm {M_S}}\). Initial length is \(\boldsymbol{\mathrm {L_{S0}}}\)

The specified velocity refers to the gravity centre of the slug, initially at the half length.

The slug specification is superimposed on the riser mass, including any internal fluid flow.

The internal crosssection area is not used in the slug modelling

The slug length is divided into sections. Initially the sections are of equal length \(\boldsymbol{\mathrm {dl_{S,0}}}\). The density, (mass per unit length) is constant within each section. Initially the mass per unit length is \(\boldsymbol{\mathrm {m_0=M_S/L_{S0}}}\)
6.4.2. Specification of slug data, one input line
TSLUG ICOSLG SLGLEN SLGMAS SLGVEL IDENS IVEL NCYCLE CYCTIM

TSLUG: real, default: 0
: Time when slug enters first end of main riser line \(\mathrm {[T]}\) 
ICOSLG: integer, default: 1
: Interruption parameter
=0
: Analysis termination controlled by slug 
=1
: Analysis termination controlled by specified length of simulation (TIME)


SLGLEN: real
: Initial slug length \(\mathrm {[L]}\) 
SLGMAS: real
: Slug mass \(\mathrm {[M]}\) 
SLGVEL: real
: Initial slug velocity \(\mathrm {[L/T]}\) 
IDENS: integer, default: 0
: Control parameter density
= 0
: Constant density 
= 1
: Variable density with vertical position


IVEL: integer, default: 0
: Control parameter velocity
= 0
: Constant velocity 
= 1
: Variable velocity 
The specified velocity refers to the gravity centre of the slug


NCYCLE: integer, default: 1
: Number of slug cycles 
CYCTIM: real
: Slug cycle time (dummy ifNCYCLE = 1
) \(\mathrm {[T]}\)
if IDENS = 1
:
Z2 SLGMA2 ZREF

Z2: real
: Second vertical position where the slug unit mass is specified \(\mathrm {[L]}\) 
SLGMA2: real
: Slug unit mass atZ2
\(\mathrm {[M/L]}\) 
ZREF: real < 0
: Reference depth \(\mathrm {[L]}\)
ZREF
< \(\mathrm {Z_{MIN}}\), where \(\mathrm {Z_{MIN}}\) is lowest vertical position along the main riser line

The unit mass at a specific zposition is calculated according to the following equation:
\(\mathrm {m(Z_i)=A(Z_iZ_{REF})^\alpha }\)
where

\(\mathrm {\alpha =\frac{ln(m_1/m_2)}{ln(\frac{Z_1Z_{REF}}{Z_2Z_{REF}})}}\)

\(\mathrm {A=\frac{m_1}{(Z_1Z_{REF})^\alpha }}\)

\(\mathrm {m_1}\):
SLGMAS/SLGLEN

\(\mathrm {m_2}\):
SLGMA2

\(\mathrm {Z_1}\): Vertical coordinate at inlet, end 1 of main riser line
if IVEL = 1
:
DELVEL VEXP

DELVEL: real
: Velocity specification 
VEXP: real
: Exponent for velocity
The unit mass at a specific zposition is calculated according to the following equation:
\(\quad \mathrm {V(Z_i)=V_1\Delta VZ_iZ_1^\alpha}\) for \(\quad \mathrm {(Z_iZ_1)>=0}\)
\(\quad \mathrm {V(Z_i)=V_1+\Delta VZ_iZ_1^\alpha}\) for \(\quad \mathrm {(Z_iZ_1)<0}\)
Where:

\(\mathrm {V_1}\): Initial slug velocity (Velocity at inlet)

\(\mathrm {\Delta V}\): DELVEL

\(\mathrm {Z_i}\): Vertical coordinate at inlet, end 1 of main riser line

\(\mathrm {\alpha }\): VEXP
6.5. Import of internal flow data from file
This data group is only given for INDINT=2
(see Nonlinear force model)
6.5.2. Specification of input flow file, one input line
IMRL CHOPAD CHFFLW

IMRL: integer, default: 0
: Main riser line number.IMRL
must be 0 in the present program version.
= 0
: All lines


CHOPAD: character(4), default: REPL
: Fluid contents option
= REPL
: Specified flow replaces that given in the Main Riser Line definition 
= ADDI
: Specified flow is in addition to that given in the Main Riser Line definition


CHFFLW: character(70)
: Name of flow data file
The flow input file is described in See Internal flow description.
6.6. Dynamic current variation
Available for nonlinear dynamic analysis, but only when the current
profile is specified explicitly on the INPMOD
input file. This means
that this data group cannot be given for coupled analysis or when the
current is specified on a CURMOD
input file. However, dynamic current
conditions can alternatively be specified using CURMOD
.
Varying current velocity and direction are specified at the current levels defined in the preceding static analysis. The varying current is to be described in a separate file. For description of the file format, confer chapter Description of Additional Input Files: Dynamic Current Variation.
6.7. Dynamic nodal forces
This data group enables the user to specify additional dynamic nodal force components. The force components may either be described by simple functions or read from a separate input file. For file description, see chapter Description of Additional Input Files: Dynamic Nodal Forces..
6.7.2. Number of specified components specified by functions or by time series on file
NDCOMP CINPUT CHFLOA

NDCOMP: integer
: Number of load components to be specified 
CINPUT: character(6), default: 'NOFILE'
: Type of force specification
CINPUT = NOFILE
: Forces described by simple expression 
CINPUT = FILE
: Forces described by time series on file


CHFLOA: character(80)
: File name for time series of force components.
Dummy if
CINPUT = NOFILE

6.7.3. Force component description
LINEID ILSEG ILNOD ILDOF CHICOO IFORTY TIMEON TIMEOF P1 P2 P3

LINEID: character(8)
: Line identifier 
ILSEG: integer
: Segment number within actual line 
ILNOD: integer
: Local node/element number within segment 
ILDOF: integer
: Degree of freedom within the specified node/element
ILDOF = 7…12
at end 2 of an element


CHICOO: character(6)
: Coordinate system code
CHICOO = GLOBAL
: Force component refers to global system, unless the node has skew or vessel boundaries. If the node has skew or vessel boundaries,CHICOO=GLOBAL
means that the load component acts in the skew (vessel) system. The force is applied at the specified node. 
CHICOO = LOCAL
: Force component refers to local system. The force is applied to the specified element.


IFORTY: integer
: Force component type
IFORTY = 1
: Constant force 
IFORTY = 2
: Harmonic force 
IFORTY = 3
: Ramp


TIMEON: real
: Time for switching component on 
TIMOFF: real
: Time for switching component off 
P1: real, default: 0
: Force component parameter
IFORTY = 1
: Magnitude, \(\mathrm {[F,FL]}\) 
IFORTY = 2
: Amplitude, \(\mathrm {[F,FL]}\) 
IFORTY = 3
: Force derivative, \(\mathrm {[F/T,FL/T]}\)


P2: real, default: 0
: Force component parameter
IFORTY = 1
: Dummy 
IFORTY = 2
: Period \(\mathrm {[T]}\) 
IFORTY = 3
: Dummy


P3: real, default: 0
: Force component parameter
IFORTY = 1
: Dummy 
IFORTY = 2
: Phase \(\mathrm {[deg]}\) 
IFORTY = 3
: Dummy

IFORTY, TIMEON, TIMEOFF, P1, P2
and P3
are dummy for
CINPUT = FILE
, time series on file. For file description, see chapter Description of Additional Input Files: Dynamic Nodal Forces..
For simulation time, t, TIMEON
⇐ t ⇐ TIMOFF
the force component \(\mathrm {(F)}\) will be applied as:

IFORTY = 1
: \(\mathrm {F=P1}\) 
IFORTY = 2
: \(\mathrm {F=P1\times sin(\frac{2\pi }{P2}\times (tTIMEON)+P3\frac{\pi }{180})}\) 
IFORTY = 3
: \(\mathrm {F=P1\times (tTIMEON)}\)
6.8. Dynamic tension variation
6.8.2. Specification of dynamic tension variation
SNODID TCX TCV TCA IOPDTV

SNODID: character(8)
: Supernode identifier for dynamic tension variation.
Must be identical to the last nodeid in stroke storage specification if stroke storage is specified.


TCX: real, default: 0
: Coefficient for tension variation due to relative displacement between vessel and riser \(\mathrm {[F/L]}\) 
TCV: real, default: 0
: Coefficient for tension variation due to relative velocity between vessel and riser \(\mathrm {[FT/L]}\) 
TCA: real, default: 0
: Coefficient for tension variation due to relative acceleration between vessel and riser \(\mathrm {[FT^2/L]}\) 
IOPDTV: integer, default: 0
: Option for updating tension during iterations (relevant for nonlinear time domain analysis only):
= 0
: Not updated 
= 1
: Updated

The resulting dynamic tension is given by:
\(\mathrm {\Delta T=TCX\times x+TCV\times \dot {x}+TCA\times \ddot {x}}\)
where \(\mathrm {x}\) is the relative vertical displacement
between the vessel and the riser. The vertical riser displacements are
directly available in a nonlinear time domain analysis. In a linear
analysis, the vertical displacements are estimated from the
displacements along lines ILIN1
…. ILINN
(as in linear stroke
calculations). File storage for
stroke response must be given if specification of
dynamic tension variation is included. In both linear and nonlinear
analyses platform motions will be modified for platform setdown if
SETLEN > 0
in File storage for
stroke response.
6.9. Time domain loading
6.9.2. Load type to be activated, one input line
LOTYPE NLSPEC CINPUT CHFLOA IFORM

LOTYPE: character
:
= SEGV
: Segment length variation (Nonlinear analysis only) 
= TEMP
: Temperature variation (Nonlinear analysis only) 
= PRES
: Pressure variation (Nonlinear analysis only) 
= BOUN
: Boundary change (Nonlinear analysis only) 
= VIVA
: Harmonic loads from VIVANA (Nonlinear analysis only) 
= WINC
: Winch run (Nonlinear analysis only) 
= WIND
: Wind event. Only available forIWITYP=14
, Stationary uniform wind with shear. 
= SHUT
: Wind turbine shutdown fault options (Nonlinear analysis only) 
= BLAD
: Wind turbine blade pitch fault options (Nonlinear analysis only)


NLSPEC: integer, default: See below
: Number of load specification to follow 
CINPUT: character, default: NOFILE
:
= NOFILE
: All load specification given below 
= FILE
: Load specification read from fileCHFLOA


CHFLOA: character, default: See below
: Load specification file.
Dummy for
CINPUT = NOFILE


IFORM: integer, default: 1
: File format
For LOTYPE = VIVA
:

NLSPEC = 1, CINPUT=FILE
andIFORM=1

The default value of
CHFLOA
is<prefix>_ifnviv.ffi
For LOTYPE = WIND
:

NLSPEC = 1, CINPUT=NOFILE
For LOTYPE = SHUT
:

NLSPEC = 1, CINPUT=NOFILE
For LOTYPE = BLAD
:

NLSPEC = 1, CINPUT=NOFILE
6.9.3. Segment length variation, NLSPEC input lines for LOTYPE = SEGV
LINEID ISEG TBEG TENO SLRATE

LINEID: character(8)
: Line identifier 
ISEG: integer
: Local segment within lineLINEID

TBEG: real
: Start time for segment length variation \(\mathrm {[T]}\) 
TEND: real
: End time for segment length variation \(\mathrm {[T]}\)
TEND > TBEG


SLRATE: real
: Segment length variation per time unit \(\mathrm {[L/T]}\)
6.9.4. Temperature variation, NLSPEC input lines if LOTYPE = TEMP
LINEID ISEG IEL TBEG TEND TEMP

LINEID: character(8)
: Line identifier 
ISEG: integer/character
: Local segment number within lineLINEID

= 0 / ALL
: All segments in specified line


IEL: integer/character
: Local element number within segmentISEG

= 0 / ALL
: All elements in specified segment


TBEG: real
: Start time for temperature variation \(\mathrm {[T]}\) 
TEND: real
: End time for temperature variation \(\mathrm {[T]}\)
TEND > TBEG


TEMP: real
: Temperature at end of temperature variation
The temperature is varied linearly during the load group from the starting temperature ending with the temperature specified here.
A linear variation of temperature over a sequence of elements may be specified by giving a negative element number at the second end of the linear variation.
6.9.5. Pressure variation, NLSPEC input lines if LOTYPE = PRES
MRLID TBEG TEND PRESSI DPRESS VVELI

MRLID: character(8)
: Reference to Main Riser Line identifier 
TBEG: real
: Start time for pressure variation \(\mathrm {[T]}\) 
TEND: real
: End time for pressure variation \(\mathrm {[T]}\)
TEND > TBEG


PRESSI: real, default: 0
: Final pressure at inlet end \(\mathrm {[F/L^2]}\) 
DPRESS: real, default: 0
: Final pressure drop \(\mathrm {[F/L^3]}\) 
VVELI: real, default: 0
: Final fluid velocity \(\mathrm {[L^3/T]}\)
Dummy in present version

6.9.6. Boundary change, 3 x NLSPEC input lines for LOTYPE = BOUN
Identification of node for boundary change
IREFID ILSEG ILNODE IOP

IREFID: character(8)
: Reference to line or supernode identifier. 
ILSEG: integer
:
If
IREFID
refers to a line,ILSEG
is the segment number within this line 
If
IREFID
refers to a supernode,ILSEG
must be zero


ILNODE: integer
:
If
IREFID
refers to a line,ILNODE
is the node number within segmentILSEG

If
IREFID
refers to a supernode,ILNODE
must be zero


IOP: integer
: Parameter for boundary change option
= 0
: Boundary conditions: fixed, prescribed or free 
= 1
: Boundary conditions: rigid node connection (The node will become a slave node.)

Ordinary (line end) supernodes and SIMO body nodes with
CHLOCA_OPT='POSI'
may have boundary change.
Status for nodal degrees of freedom if IOP = 0
IPOS IX IY IZ IRX IRY IRZ

IPOS: integer
: Boundary condition type
IPOS = 0
: The node is fixed in global system 
IPOS = N
: The node is attached to support vessel no N


IX: integer
: Boundary condition code for translation in Xdirection
IX = 0
: Free 
IX = 1
: Fixed of prescribed


IY: integer
: Boundary condition code for translation in Ydirection
Same interpretation as for
IX
.


IZ: integer
: Boundary condition code for translation in Zdirection
Same interpretation as for
IX
.


IRX: integer
: Boundary condition code for rotation around Xdirection
Same interpretation as for
IX
.


IRY: integer
: Boundary condition code for rotation around Ydirection
Same interpretation as for
IX
.


IRZ: integer
: Boundary condition code for rotation around Zdirection
Same interpretation as for
IX
.

6.9.7. Specification of harmonic loads from VIVANA, one input line for LOTYPE = VIVA
CHFRQ ALIM ISEED TPLOT

CHFRQ: character, default: DOMI
:
= ALL
: All responses frequencies fromVIVANA
included 
= AMIN
: Response frequencies with normalized crossflow response larger thanAMIN
included 
= DOMI
: Only the dominating response frequency included


ALIM: real, default: 0
: Crossflow displacement to diameter ratio \(\mathrm {[1]}\)
Dummy for
CHFRQ
\(\mathrm {\neq }\)ALIM


ISEED: integer, default: 280495
: Seed 
TPLOT: real, default: 2
: VIV response plot interval. Key VIV results from the lastTPLOT
interval of the simulation are stored on the_dynmod.mpf
file
TPLOT > 0
: Given as number of whole response periods 
TPLOT < 0
: Given as time \(\mathrm {[T]}\)

6.9.8. Winch run, NLSPEC input lines for LOTYPE = WINC
IWINCH TBEG TEND WIVEL

IWINCH: integer
: Winch number 
TBEG: real
: Start time for winch run \(\mathrm {[T]}\) 
TEND: real
: End time for winch run \(\mathrm {[T]}\) 
WIVEL: real
: Winch velocity \(\mathrm {[L/T]}\)
WIVEL > 0
: Winching out, i.e. the winch run will increase the active line length.

6.9.9. Wind event specification, two or three input lines for LOTYPE = WIND
In the following IEC 2005 refers to the standard IEC 614001 Wind turbines  Part 1: Design requirements  2005
.
An IEC 2005 extreme wind event may only be applied to a stationary
uniform wind with shear, IWITYP=14
.
Note that this input option is only available if one and only one wind turbine is specified in the system.
Start time and wind turbine reference
TIME WINDTURBINEID

TIME: real
: Start time for wind event \(\mathrm {[T]}\) 
WINDTURBINEID: character(8)
: Wind turbine identifier given inINPMOD
.NONE
may be given to skip the wind turbine reference for the events ECD, EOG and EDC withCLASS = NONE
; i.e. detailed specification of event.
Extreme wind event
CHEVEN CLASS CHDIR

CHEVEN: character(12)
: Extreme wind event. The following values are currently available:
= IEC2005_ECD
: IEC 2005 extreme coherent gust with direction change 
= IEC2005_EWSV
: IEC 2005 extreme vertical wind shear 
= IEC2005_EWSH
: IEC 2005 extreme horizontal wind shear 
= IEC2005_EOG
: IEC 2005 extreme operating gust 
= IEC2005_EDC
: IEC 2005 extreme direction change


CLASS: character(4)
: Wind turbine class, ref IEC 2005. Legal values areIA
,IIA
,IIIA
,IB
,IIB
,IIIB
,IC
,IIC
,IIIC
,S
orNONE
, detailed specification of event parameters. 
CHDIR: character(4)
: Direction of event. Dummy forCHEVEN = IEC2005_EOG
.
= POS
: For ECD and EDC, the wind shifts clockwise (viewed from above). For EWSV, the wind increases at the top of the rotor disk and decrease at the bottom. For EWSH, the wind increases on the left side of the rotor disk and decrease on the right side when viewed along the shaft from the hub. 
= NEG
: For ECD and EDC, the wind shifts counterclockwise (viewed from above). For EWSV, the wind decreases at the top of the rotor disk and increases at the bottom. For EWSH, the wind decreases on the left side of the rotor disk and increases on the right side when viewed along the shaft from the hub. 
= NONE
: Only allowed forCHEVEN = IEC2005_EOG
.

Additional input for wind turbine class S
If CLASS = S
, the following additional input line is given:
VREF IREF

VREF: real
: Reference wind speed average over 10 min \(\mathrm {[L/T]}\) 
IREF: real
: Expected value of the turbulence intensity at 15 m/s \(\mathrm {[1]}\)
Detailed specification of IEC2005 ECD event
If CLASS = NONE
and CHEVEN = IEC2005_ECD
, the following additional
input line is given:
VEL_EVENT DIR_EVENT TIME_EVENT

VEL_EVENT: real, default: 0.0
: Velocity change \(\mathrm {[L/T]}\) 
DIR_EVENT: real, default: 0.0
: Direction change \(\mathrm {[deg]}\) 
TIME_EVENT: real > 0
: Duration of event \(\mathrm {[T]}\)
Detailed specification of IEC2005 EWSV or EWSH event
If CLASS = NONE
and CHEVEN = IEC2005_EWSV or IEC2005_EWSH
, the
following additional input line is given:
VEL_EVENT TIME_EVENT

VEL_EVENT: real, default: 0.0
: Maximum velocity change at edge of rotor \(\mathrm {[L/T]}\) 
TIME_EVENT: real > 0
: Duration of event \(\mathrm {[T]}\)
Detailed specification of IEC2005 EOG event
If CLASS = NONE
and CHEVEN = IEC2005_EOG
, the following additional
input line is given:
VEL_EVENT TIME_EVENT

VEL_EVENT: real, default: 0.0
: Range of velocity from minimum to maximum during the event \(\mathrm {[L/T]}\) 
TIME_EVENT: real > 0
: Duration of event \(\mathrm {[T]}\)
6.9.10. Wind turbine shutdown fault options
The specifications given for turbine shutdown will overrule commanded blade pitch and torque, given by the wind turbine control system. Wind turbine blade pitch faults will override the wind turbine shutdown options.
Note that this input option is only available if one and only one wind turbine is specified in the system.
Start time and wind turbine reference
TSTART WINDTURBINEID

TSTART: real
: Start time for shutdown \(\mathrm {[T]}\) 
WINDTURBINEID: character(8)
: Reference to wind turbine identifier
Number of pairs in rate of change in pitch and maximum pitch
NPAIR

NPAIR: integer
: Number of pairs in tabulated rate of pitch change and maximum pitch at the rate of pitch change
Rate of change in pitch and maximum pitch at the rate of change in pitch, NPAIR input lines
RATE MAX_PITCH

RATE: real
: Rate of change in pitch angle (absolute value) \(\mathrm {[deg/T]}\)
RATE > 0


MAX_PITCH: real
: Maximum pitch angle for the rate of change in pitch \(\mathrm {[deg]}\)
MAXPITCH > 0

MAX_PITCH
values must be given in increasing order.
Example:
Type of shutdown  Pitch change rate  Maximum pitch 

normal 
1.0 deg/T to 
90.0 deg 
Example:
Type of shutdown  Pitch change rate  Maximum pitch 

openloop 
8.0 deg/T to 
40.0 deg 
 
4.0 deg/T to 
90.0 deg 
Example:
Type of shutdown  Pitch change rate  Maximum pitch 

emergency 
8.0 deg/T to 
90.0 deg 
Generator torque fault options
CHFAULT

CHFAULT: character(6)
:
= NONE
: No generator torque fault, the calculated generator torque will be applied in full 
= LOSS
: Total loss of generator torque 
= BACKUP
: Backup power, generator torque will follow scaled torque control

Mechanical brake option
CHBRAKE

CHBRAKE: character(6)
:
= NONE
: No mechanical brake 
= BRAKE
: Mechanical brake (Linear damping)

Torque damping coefficient and brake uploading duration, One input line for CHBRAKE = BRAKE
TORQUE_DAMP UPL_DURATION

TORQUE_DAMP: real
: Linear torque damping coefficient \(\mathrm {[FLT/deg]}\)
TORQUE_DAMP >= 0


UPL_DURATION: real
: Brake uploading duration to full braking torque \(\mathrm {[T]}\)
UPL_DURATION >= 0

6.9.11. Wind turbine blade pitch fault options
Wind turbine blade pitch faults will override commanded blade pitch given by the wind turbine control system or by the wind turbine shutdown options.
Note that this input option is only available if one and only one wind turbine is specified in the system.
Wind turbine reference
WINDTURBINEID

WINDTURBINEID: character(8)
: Reference to wind turbine identifier
Number of blades for fault specification
NBL_FAULT

NBL_FAULT: integer
: Number of blades for fault specification
NBL_FAULT >= 0

The subsequent input specification must be given per blade with pitch fault
Start time and line (foil blade) reference for fault specification
TSTART LINEID

TSTART: real
: Start time for blade pitch fault \(\mathrm {[T]}\) 
LINEID: character(8)
: Reference to line identifier
Type of blade pitch fault
CHFAULT

CHFAULT: character(4)
:
= SEIZ
: Seized  Fixed pitch from time of occurrence 
= RUNA
: Runaway  Pitch change rate from time of occurrence to final pitch 
= BIAS
: Actuator bias  Fixed pitch fault from time of occurrence

6.10. File storage of displacement response
Before specifying file storage of response, note that meaningful output
from OUTMOD
can be dependent on which and how much information that is
stored on file from DYNMOD
. Examples of such output options in
OUTMOD
are time series of element angles and distance between
elements, see
Element angle time series from time domain analysis
and Distance time series calculated from the time domain analyses.
There are limitations in storage capacity due to: Disk/user size 
6.10.2. Specification of displacements to be stored
Amount of storage, one input line
IDISP NODISP IDISFM

IDISP: integer
: Code for storage of nodal displacements. Storage for everyIDISP
time step (IDISP=2
gives storage for every second step). 
NODISP: integer > 0
: Number of input lines given specifying node numbers where displacements are stored. 
IDISFM: integer, default: 0: integer
: Format code for storage and/or output of nodal displacements.
IDISFM = 0
: Storage only onifndyn
file. 
IDISFM = 1
: Storage onifndyn
file and additional file in ASCII format. 
IDISFM = 2
: Storage onifndyn
file and additional file in BINARY format. 
IDISFM = 1
: Storage only on additional file in ASCII format. Results are not available inOUTMOD
. 
IDISFM = 2
: Storage only on additional file in BINARY format. Results are not available inOUTMOD
.

Note that data must be stored on the ifndyn
file in order to be
available for OUTMOD
.
If IDISFM
\(\mathrm {\neq }\) 0
is specified, an additional
result file and a key file will be created. The file names will be based
on the name of the DYNMOD
result file; <prefix>_dynmod.res
. An
additional ASCII file will be <prefix>_noddis.asc
and an additional
binary file will be <prefix>_noddis.bin
. The key file
key_<prefix>_noddis.txt
will describe how data is stored on the
additional output file. The key file may be viewed in a text editor.
Specification of nodes for displacement storage, NODISP input lines
LINEID ISEG INOD

LINEID: character(8)
: Line identifier 
ISEG: integer
: Segment number of line 
INOD: integer/character
: Local node number on actual segment
Consecutively numbered nodes may be specified implicitly by assigning a
negative value to the last of two adjacent INOD
. In this case
LINEID
and ISEG
must be the same for the two nodes.
All nodes within one segment may be specified by simply giving ALL
as
input to INOD
.
6.11. File storage for internal forces
6.11.2. Specification of forces to be stored
Amount of storage, one input line
IFOR NOFORC IFORFM IELTFM IBOTFM

IFOR: integer
: Code for file storage of internal forces. Forces are stored for everyIFOR
time step. (IFOR=3
gives storage for every third step) 
NOFORC: integer > 0
: Number of input lines given to specify elements for which forces are stored. 
IFORFM: integer, default: 0
: Format code for storage and / or output of element forces
IFORFM = 0
: Storage only onifndyn
file 
IFORFM = 1
: Storage onifndyn
file and additional file in ASCII format 
IFORFM = 2
: Storage onifndyn
file and additional file in BINARY format 
IFORFM = 1
: Storage only on additional file in ASCII format. Results are not available inOUTMOD
. 
IFORFM = 2
: Storage only on additional file in BINARY format. Results are not available inOUTMOD
.


IELTFM: integer, default: 0
: Format code for output of element transformation matrices
IELTFM = 0
: No output 
IELTFM = ±1
: Output on additional file in ASCII format 
IELTFM = ±2
: Output on additional file in BINARY format


IBOTFM: integer, default: 0
: Format code for output of seafloor / soil contact results. Nonlinear analysis only.
IBOTFM = 0
: No output 
IBOTFM = ±1
: Output on additional file in ASCII format 
IBOTFM = ±2
: Output on additional file in BINARY format

Note that data must be stored on the ifndyn
file in order to be
available for OUTMOD
.
If IFORFM
\(\mathrm {\neq }\) 0
is specified, an additional
result file and a key file will be created. The file names will be based
on the name of the DYNMOD
result file; <prefix>_dynmod.res
. An
additional ASCII file will be <prefix>_elmfor.asc
and an additional
binary file will be <prefix>_elmfor.bin
. The key file
key_<prefix>_elmfor.txt
will describe how data is stored on the
additional output file. The key file may be viewed in a text editor.
For nonlinear analysis with pipeinpipe elements, the contact forces
will be written to <prefix>_cntfor.asc
or .bin
if
IFORFM
\(\mathrm {\neq }\) 0
. The contents are described on
the corresponding key file key_<prefix>_cntfor.txt
.
Roller contact forces will be stored on separate result files if
IDCOM = LAYFLX
, see
INPMOD: Selection of riser type and identifier.
If IELTFM
\(\mathrm {\neq }\) 0
is specified, element
transformation matrices will be written to an additional result file for
elements for which force storage is specified. The file name will be
based on the name of the DYNMOD
result file; <prefix>_dynmod.res
. An
additional ASCII file will be <prefix>_elmtra.asc
and an additional
binary file will be <prefix>_elmtra.bin
. The key file
key_<prefix>_elmtra.txt
will describe how data is stored on the
additional output file. The key file may be viewed in a text editor.
If IBOTFM
\(\mathrm {\neq }\) 0
is specified, results for
seafloor contact elements and / or soil layer profile contact elements
will be written to an additional file for contact elements that are
attached to beam or bar elements for which force storage is specified.
The file name will be based on the name of the DYNMOD
result file;
<prefix>_dynmod.res
. An additional ASCII file will be
<prefix>_botres.asc
and an additional binary file will be
<prefix>_botres.bin
. The key file key_<prefix>_botres.txt
will
describe how data is stored on the additional output file. The key file
may be viewed in a text editor.
Specification of elements for force storage, NOFORC input lines
LINEID ISEG IEL

LINEID: character(8)
: Line identifier 
ISEG: integer
: Local segment number within lineLINEID

IEL: integer/character
: Local element number within segmentISEG

= ALL
: All elements in specified segment

Consecutively numbered elements may be specified implicitly by assigning
a negative value to the last of two adjacent elements, IEL
. In this
case LINEID
and ISEG
must be the same for the two elements.
All elements within one segment may be specified by simply giving ALL
as input to IEL
.
6.12. File storage for curvature response
Curvature estimates based on nodal displacements may be generated by
OUTMOD
(see
Curvature time series calculated from dynamic nodal displacements)
even though curvatures are not stored from DYNMOD
.
6.12.2. Specification of curvature to be stored
Amount of storage, one input line
ICURV NOCURV ICURFM

ICURV: integer
: Code for storage of curvature response. Curvature is stored for everyICURV
time step 
NOCURV: integer > 0
: Number of input lines given to specify elements for which curvatures are stored. 
ICURFM: integer, default: 0: integer
: Format code for storage and/or output of element curvature.
ICURFM = 0
: Storage only onifndyn
file. 
ICURFM = 1
: Storage onifndyn
file and additional file in ASCII format. 
ICURFM = 2
: Storage onifndyn
file and additional file in BINARY format. 
ICURFM = 1
: Storage only on additional file in ASCII format. Results are not available inOUTMOD
. 
ICURFM = 2
: Storage only on additional file in BINARY format. Results are not available inOUTMOD
.

Note that data must be stored on the ifndyn
file in order to be
available for OUTMOD
.
If ICURFM
\(\mathrm {\neq }\) 0
is specified, an additional
result file and a key file will be created. The file names will be based
on the name of the DYNMOD
result file; <prefix>_dynmod.res
. An
additional ASCII file will be <prefix>_elmcur.asc
and an additional
binary file will be <prefix>_elmcur.bin
. The key file
key_<prefix>_elmcur.txt
will describe how data is stored on the
additional output file. The key file may be viewed in a text editor.
Specification of elements for curvature storage, NOCURV input lines
LINEID ISEG IEL

LINEID: character(8)
: Line identifier 
ISEG: integer
: Local segment number within lineLINEID

IEL: integer/character
: Local element number within segmentISEG

= ALL
: All elements in specified segment

Consecutively numbered elements may be specified implicitly by assigning
a negative value to the last of two adjacent elements, IEL
. In this
case LINEID
and ISEG
must be the same for the two elements.
All elements within one segment may be specified by simply giving ALL
as input to IEL
.
6.13. File storage for hydrodynamic loads
6.13.2. Specification of forces to be stored
Amount of storage, one input line
IHLO NOHLO IHLOFM

IHLO: integer
: Code for file storage of hydrodynamic loads. Forces are stored for everyIHLO
time step. (IHLO=4
gives storage for every fourth simulation step) 
NOHLO: integer > 0
: Number of input lines given to specify elements for which hydrodynamic loads are stored. 
IHLOFM: integer, default: 0
: Format code for storage of hydrodynamic loads
IFORFM = 1
: Storage on the ASCII file<prefix>_hydloa.asc

IFORFM = 2
: Storage on the BINARY file<prefix>_hydloa.bin

The key file key_<prefix>_hydloa.txt
will describe how data is
stored on the file. The key file may be viewed in a text editor.
Specification of elements for hydrodynamic load storage, NOFHLO input lines
LINEID ISEG IEL ILEVHLO

LINEID: character(8)
: Line identifier 
ISEG: integer
: Local segment number within lineLINEID

= 0
: All segments in the specified line


IEL: integer
: Local element number within segmentISEG

= 0
: All elements in the specified segment


ILEVHLO: integer, 0<ilevhlo<4, default: 1
: Level of output.
= 1
: Minimum: Total hydrodynamic load excepting added mass contribution 
= 2
: Medium: Available for elements with time domain VIV loading only. Total hydrodynamic load excepting added mass contribution, average relative velocity, average crossflow, inline and higher harmonic load amplitude 
= 3
: Maximum: Available for elements with time domain VIV loading only. Total hydrodynamic load excepting added mass contribution, relative velocity at both ends, Morison, crossflow, inline and higher order loads at both ends.

6.14. Envelope curve specification
This data group enables the user to compute envelopes from both regular and irregular analysis. For irregular analysis mean and standard deviation of response will be printed on the _dynmod.res file.
6.14.2. Specification
Options for calculation and printing
IENVD IENVF IENVC TENVS TENVE NPREND NPRENF NPRENC IFILMP

IENVD: integer, default: 1
: Calculation option for displacement envelopes
= 0
: not calculated 
= 1
: calculated


IENVF: integer, default: 1
: Calculation option for force envelopes
= 0
: not calculated 
= 1
: calculated


IENVC: integer, default: 1
: Calculation option for curvature envelopes
= 0
: not calculated 
= 1
: calculated


TENVS: real
: Simulation start time for calculating envelopes \(\mathrm {[T]}\) 
TENVE: real, default:
\(\mathrm {10^{6}}\): Simulation end time for calculating envelopes \(\mathrm {[T]}\) 
NPREND: integer, default: 0
: Print option for displacement envelopes
= 0
: Not printed 
= 1
: print


NPRENF: integer, default: 0
: Print option for force envelopes
= 0
: not printed 
= 1
: print


NPRENC: integer, default: 0
: Print option for curvature envelopes
= 0
: not printed 
= 1
: print


IFILMP: integer, default: 2
: MatrixPlot file option; specifies amount of results written to the file<prefix>_dynmod.mpf
.0 ⇐ IFILMP ⇐ 4
.
= 0
: No print 
= 1
: Minimum values, maximum values and standard deviations 
= 2
: Minimum values, maximum values and standard deviations (identical to specifyingIFILMP = 1
) 
= 3
: Minimum values, maximum values, standard deviations, mean values and meancrossing periods 
= 4
: Minimum values, maximum values, standard deviations, mean values, meancrossing periods, skewness and kurtosis

Note that the meancrossing period, skewness and kurtosis will be inaccurate for time series with constant or near constant values.
6.15. File storage for stroke response
The stroke is stored for presentation and / or postprocessing in
OUTMOD
6.15.2. Specification of stroke calculation and storage
ISTRO SNODID IOPSTR SETLEN XRSTRO YRSTRO NLINST LINEID1 .. LINEIDnlinst

ISTRO: integer, default: 1
: Code for storage of stroke response. Storage for everyISTRO
time step (ISTRO=2
gives storage for every second step) 
SNODID: character(8)
: Supernode identifier for stroke calculation 
IOPSTR: integer, default: 0
: Option for reference coordinates
= 0
: Initial stressfree configuration used as reference 
= 1
: Final static configuration used as reference (under implementation)


SETLEN: real, default: 0
: Tendon length for setdown correction 
XRSTRO: real, default: 0
: Global X coordinate of nodeINODST
’s reference point for setdown calculations.
Dummy of
SETLEN = 0
.


YRSTRO: real, default: 0
: Global Y coordinate of nodeINODST
’s reference point for setdown calculations.
Dummy of
SETLEN = 0
.


NLINST: integer, default: 0
: Number of lines used in calculating stroke
Dummy for nonlinear analysis


Lines (line identifiers) used in stroke calculation

Dummy for nonlinear analysis

LINEID1: character(8)
: 
.

.

.

LINEIDnlinst: character(8)
:

Stroke may only be calculated for supernodes. No setdown correction if
SETLEN = 0.0
6.16. File storage for sum forces
The element sum forces are the sum of the stiffness, damping and inertia forces. The sum force in the local axial direction will be stored for each specified element.
6.16.2. Specification of forces to be stored
Amount of storage, one input line
ISFOR NOSFOR ISFOFM

ISFOR: integer
: Code for file storage of sum forces. Forces are stored for everyISFOR
time step (ISFOR=3
gives storage for every third step) 
NOSFOR: integer > 0
: Number of input lines given to specify elements for which sum forces are stored. 
ISFORM: integer, default: 1: integer
: Format code for storage and/or output of sum element forces.
ISFORM = 1
: Storage on additional file in ASCII format only. 
ISFORM = 2
: Storage on additional file in BINARY format only.

This data group is available for nonlinear time domain analysis only.
If ISFORM
\(\mathrm {\neq }\) 0
is specified, an additional
result file and a key file will be created. The file names will be based
on the name of the DYNMOD
result file; <prefix>_dynmod.res
. An
additional ASCII file will be <prefix>_elmsfo.asc
and an additional
binary file will be <prefix>_elmsfo.bin
. The key file
key_<prefix>_elmsfo.txt
will describe how data is stored on the
additional output file. The key file may be viewed in a text editor.
Note that axial force presented by other data groups is the element effective tension, where only internal forces from the stiffness are included. The damping and inertia forces in the other elements are included inherently through nodal displacements. It is only the internal element mass and damping forces in the element that are not included.
The element sum forces presented by this data group also include damping and inertia forces for the element. The element sum forces can be viewed as an equivalent to reaction forces at the end of the element.
Specification of elements for force storage, NOSFOR input lines
LINEID ISEG IEL

LINEID: character(8)
: Line identifier 
ISEG: integer
: Local segment number within lineLINEID

IEL: integer/character
: Local element number within segmentISEG

= ALL
: All elements in specified segment

Consecutively numbered elements may be specified implicitly by assigning
a negative value to the last of two adjacent elements, IEL
. In this
case LINEID
and ISEG
must be the same for the two elements.
All elements within one segment may be specified by simply giving ALL
as input to IEL
.
6.17. File storage of support forces
This option enables export of support forces to a binary file.
6.17.1. Data group identifier, one input line
SUPPort FORCe STORage
Amount of storage, one input line
DT_SFOR NS ISFOR

DT_SFOR: real, default: 0
: Desired time interval for storage [T]
= 0
: Storage at each simulation time step


NS: integer > 0: integer
: Number of input lines given to specify the SIMO bodies and support vessel for storage of support forces. 
ISFOR: integer, default: 2: integer
: File format code for storage
= 1
: ASCII format 
= 2
: Storage on file in binary format.

Note that DT_SFOR
will be adjusted to get an integer ratio between the
simulation time step DT
and the specified storage interval DT_SFOR
.
Support force identification for storage, NS
input lines
SFOR CHCOR

SFOR : character(8) or integer
: SIMO body or support vessel identifier 
CHCOR: character(8), default= BVLOC
: Coordinate system for support forces
= GLOB
: Global coordinate system 
= BVLOC
: SIMO body of support vessel coordinate system

Note that that the support vessel is given as integer input. The SIMO body has an character ID as identifier.
6.18. File storage for wind turbine responses
This option enables export of wind turnine key responses to file in binary or ASCII format
6.18.1. Data group identifier, one input line
TURBine RESPonse STORage
Time interval for storage, one input line
DT_WTR

DT_WTR: real
: Desired time interval for storage [T]
DT_WTR = 0
: Storage at each simulation time step

Note that DT_WTR
will be adjusted to get an integer ratio between the
simulation time step DT
and the specified storage interval DT_WTR
.
Amount of storage, one input line
NOTURB ITURBFM

NOTURB: integer
: Number of wind turbines for storage 
ITURBFM: integer
: File format code for storage
ITURBFM = 1
: Storage on file in ASCII format. 
ITURBFM = 2
: Storage on file in binary format.

The wind turbine responses are written to <prefix>_witurb.asc
or
<prefix>_witurb.bin
.
The contents are described in key_<prefix>_witurb.txt
6.19. File storage for wind turbine blade responses
This option enables export of wind turbine blade responses to file in binary or ASCII format.
6.19.1. Data group identifier, one input line
WTBLade RESPonse STORage
Specification of the amount of responses, one input line
AMOUNT

AMOUNT: character(3)
: Amount of blade responses storage
AMOUNT = MIN
: Minimum amount of responses:
Drag and lift force intensities in foil system

Relative wind velocity in foil system  Angle of attack in foil system


AMOUNT = MED
: Medium amount of responses. In addition to minimum amount:
Drag, lift and moment coefficients in foil system

Induced wind speed in foil system

Remote incoming wind speed including tower effect in foil system

Separation point position in foil system

Axial and tangential induction factors in rotor system

Axial and tangential load intensities in rotor system

Annulus average axial and tangential induction velocity


AMOUNT = MAX
: Maximum amount of responses. In addition to medium amount:
Transformation matrix between foil and rotor systems


Time interval for storage, number of input lines and file format code, one input line
DT_TBR NOSPEC IBLADFM

DT_TBR: real
: Desired time interval for storage [T]
DT_TBR = 0
: Storage at each simulation time step


NOSPEC: integer > 0
: Number of input lines given to specify elements for which blade responses are stored. 
IBLADFM: integer
: File format code for storage
IBLADFM = 1
: Storage on file in ASCII format. 
IBLADFM = 2
: Storage on file in binary format.

Note that DT_TBR
will be adjusted to get an integer ratio between the
simulation time step DT
and the specified storage interval DT_TBR
.
The wind turbine responses are written to <prefix>_blresp.asc
or
<prefix>_blresp.bin
. <
The contents are described in key_<prefix>_blresp.txt
Specification of elements for blade response storage, NOSPEC input lines
LINEID ISEG IEL

LINEID: character(8)
: Line identifier 
ISEG: integer/character
: Local segment number within lineLINEID

IEL: integer/character
: Local element number within segmentISEG
All elements within the line may be specified by simply giving ALL
as
input to ISEG
. Thus IEL
will be dummy input.
All elements within one segment may be specified by giving ALL
as
input to IEL
.
6.20. Export of element responses
This option enables export of element responses for subsequent communication with general advanced animation tools. The instruction is applicable for nonlinear dynamic analysis only.
6.20.2. Amount of response storage and file format, one input line
TCONDS TCONDE DELT CHFORM

TCONDS: real, default: 0
: Start time for export 
TCONDE: real, default:
\(\mathrm {10^5}\): End time for export 
DELT: real, default: See below
: Time increment for export 
CHFORM: character
:
= VIS
: Export to file format used by the computer program SIMVIS for response visualization subsequent to dynamic analysis 
= RAF
: Export to file format of type RAF

Default values of DELT
:

DTWF
: Time increment used for presampling of irregular waves and prescribed motions 
DT
: Time increment used in time integration for regular analysis
6.20.3. Detailed specification of exported element responses
This data group is optionally given for CHFORM = VIS
In present version it is possible to specify element responses in form of effective tension, resulting curvature and longitudinal stress (if available). By default all available element responses for all lines will be exported. This input line makes it possible limit or specify response types for selected lines in the system.
Number of input lines: as many as necessary.
OPTION CHRESP CHILIN

OPTION: character
:
= STORE

= NOSTORE


CHRESP: character
: Response type to be exported
= EFFAXFORCE
: Effective tension 
= RESCURV
: Resultant curvature 
= LONGSTRESS
: Longitudinal stress 
= ALL
: All of the above described responses


CHILIN: character
:
= LINEID
: Line identifier 
= ALL
: All lines

7. Description of Additional Input Files
7.1. Dynamic Current Variation
The file CHFCUR
specified in Dynamic current variation, contains
the description of dynamic current variation. The file is a free format
sequential ASCIIfile.
The current velocity and direction have to be specified at all levels defined in the preceding static analysis. The static current profile is interpreted as the current profile at time equal to zero. The dynamic current profile is described at an arbitrary number of time instants, given by increasing values. Linear interpolation is used for intermediate values. If the last defined time instant is exceeded during simulation, the current profile is assumed constant and equal to the last specification for the continued simulation.
File description
7.1.1. Number of specified time instants, one input line
NDYCUR

NDYCUR: integer > 1
: The number of time instants for which current profile is given.
The input data in Number of levels and time instant, one input line
and Current velocity and direction, one input line per current level,
i.e. NLCUR input lines
(below) must be given in one block for each
defined time instant.
Number of levels and time instant, one input line
NLCUR TIMDCU

NLCUR: integer
: Number of levels in current profile. The number of levels has to be equal the number used in the preceding static analysis 
TIMDCU: real > 0
: Time instant for the specified current profile \(\mathrm {[T]}\)
Current velocity and direction, one input line per current level, i.e. NLCUR input lines
CURDIR CURVEL CURVEZ

CURDIR: real
: Direction of current velocity.
The angle is measured in degrees from global xaxis counter clockwise to the current vector, confer Current parameters


CURVEL: real, default: 0
: Current velocity \(\mathrm {[L/T]}\) 
CURVEZ: real, default: 0
: Vertical current velocity \(\mathrm {[L/T]}\)
7.2. Dynamic Nodal Forces
The file CHFLOA
specified in Dynamic nodal forces, contains
the description of dynamic nodal load components; i.e. userdeined
external dynamic loads given as time series. The file is a free format
sequential ASCIIfile. Two alternative formats are available; the
original format with multiple input lines for each time instant loads
are specified for and the column format with one line for each time
instant loads are specified for. The first input line in the file is
used to determine which format the file is read in. If only one number
is found on the first input line, the file is read using the original
format. If more than one number is found, the file is read using the
column format.
The dynamic nodal load components are described by values at specified time instants, which must be increasing. Intermediate values are found by linear interpolation. Between the start of the simulation and the first time instant with specified loads, the loads are linearly increased from zero to the first values given. If the simulation continues after the last defined time instant, the nodal load components are kept constant at the last values given.
The number of nodal load components, location and direction are defined in Dynamic nodal forces. This data group also defines the order in which the load components are to be specified on the file.
7.2.2. Number of specified time instants, one input line
NTDFO

NTDFO: integer >= 1
: Number of time instants for which nodal load components are specified.
The input data in Number of load components and time instant, one input line
and Load components, MDCOMP input lines
(below) must be given in
one block for each defined time instant.
7.2.3. Number of load components and time instant, one input line
MDCOMP TIMDFO

MDCOMP: integer
: Number of load components.
Used for control:
MDCOMP = NDCOMP

NDCOMP
is specified in Dynamic nodal forces


TIMDFO: real > 0
: Time instant for the specified load components \(\mathrm {[T]}\)
7.3. Diffracted Wave Transfer Functions at Points
The file CHFDIF
specified in Irregular Waves contains
the wave kinematics transfer functions.
7.3.2. Text describing the linear incoming wave to diffracted wave transfer functions, two input lines
TXDI1

TXDI1: character(60)
: Character string
7.3.3. Point reference, one input line
PTNOUS IVES

PTNOUS: integer
: Point number defined by user 
IVES: integer
: Support vessel number
7.3.4. Point coordinates, one input line
XBDY YBDY ZBDY

XBDY: real
: xcoordinate of where transfer function is calculated, given in support vessel coordinate system \(\mathrm {[L]}\) 
YBDY: real
: ycoordinate of where transfer function is calculated, given in support vessel coordinate system \(\mathrm {[L]}\) 
ZBDY: real
: zcoordinate of where transfer function is calculated, given in support vessel coordinate system \(\mathrm {[L]}\)
7.3.5. Dimensioning parameters, one input line
NDIR NFRE ITYPIN

NDIR: integer
: Total number of wave directions (for this point) 
NFRE: integer
: Total number of frequencies (for this point) 
ITYPIN: integer
: Code for which format the transfer functions are given in
= 1
: Complex form 
= 2
: Amplitude ratio \(\mathrm {[1]}\) and phase \(\mathrm {[deg]}\) 
= 3
: Amplitude ratio \(\mathrm {[1]}\) and phase \(\mathrm {[rad]}\)

7.3.7. Directions, NDIR input lines
IDIR DIR

IDIR: integer
: Direction number (between 1 andNDIR
) 
DIR: real
: Propagation direction of incoming wave, \(\mathrm {[deg]}\)
7.3.9. Frequencies, NFRE input lines
IFRE FRE

IFRE: integer
: Frequency number (between 1 andNFRE
) 
FRE: real
: Angular frequency of incoming wave, \(\mathrm {[rad/T]}\)
7.3.10. Data identification, one input line
WAVE ELEVation DIFFracted wave transfer function
or
XVELocity DIFFracted WAVE transfer function
YVELocity DIFFracted WAVE transfer function
ZVELocity DIFFracted WAVE transfer function
7.3.11. Diffracted wave transfer function, NDIR x NFRE input lines
IDIR IFRE A B

IDIR: integer
: Direction number 
IFRE: integer
: Frequency number 
A: real
: Interpretation according to value ofITYPIN

ITYPIN = 1
: Real part 
ITYPIN = 2
: Amplitude ratio \(\mathrm {[1],[rad/m]}\) 
ITYPIN = 3
: Amplitude ratio \(\mathrm {[1],[rad/m]}\)


B: real
: Interpretation according to value ofITYPIN

ITYPIN = 1
: Imaginary part 
ITYPIN = 2
: Phase angle \(\mathrm {[deg]}\) 
ITYPIN = 3
: Phase angle \(\mathrm {[rad]}\)

Transfer functions for accelerations will be calculated based on velocity transfer functions
7.4. Internal flow description
The file "CHFFLW" specified in Import of internal flow data from file contains a description of the timevarying internal flow.
7.4.1. Heading, one input line

<TEXT>: character(78)
:
The heading will be echoed on the <prefix>_dynmod.res
result file.
7.4.2. Specification of internal flow conditions.
Data groups Specification of time…
and Specification of flow
conditions…
(below) are repeated as many times as necessary. At least
two time steps must be given.
Specification of time, one input line
CHIDEN TIME

CHIDEN: character(4)
:
= TIME


TIME: real
: Time for the following specified flow conditions
Specification of flow conditions, as many input lines as needed. (Zero input lines may be given.)
IFE1 IFE2 DEN VEL

IFE1: integer
: First flow element with these conditions 
IFE2: integer
: Last flow element with these conditions 
DEN: real
: Density of contents \(\mathrm {[M/L^3]}\) 
VEL: real
: Velocity of contents \(\mathrm {[L/T]}\)
The elements in the MRL(s) are numbered consecutively along the MRL. A
table of the flow element numbering may be found on the
<prefix>_stamod.res
file.