1. Stress joint line specification

1.1. Data group identifier, one input line

The stress joint lines are labelled with an unique line type identifier, LINTYP-ID. The total number of line types and stress joints has to be less or equal to 500 in the present version.

STREss JOINt DATA

1.2. Stress joint specification, one input line

LINTYP-ID CDSJ CMASJ NSJSEC FLUTYP

  • LINTYP-ID: character(8): Line type identifier

  • CDSJ: real: Non-dimensional quadratic drag coefficient in normal direction

  • CMASJ: real: Non-dimensional added mass coefficient in normal direction

  • NSJSEC: integer: Number of conical sections in stress joint

  • FLUTYP: character/integer: Reference to internal fluid component type identifier, CMPTYP-ID.

    • Must be of type FLUID.

    • FLUTYP = 'NONE' or '0' means no fluid in the line.

1.3. Hydrodynamic load type identification, One optional input line

CHLOAD

  • CHLOAD: character: = HYDR - Text to identify hydrodynamic coefficients

Note: Required if non-Morison loads are to be specified

Load type identification if CHLOAD=HYDR, One input line
CHTYPE

  • CHTYPE: character: Hydrodynamic load type

    • = NONE: No hydrodynamic load coefficients

    • = MORI: Slender element hydrodynamic coefficients

    • = TVIV: Time domain VIV load coefficients. Restricted option.

Note that the option TVIV is currently under development.

Hydrodynamic force coefficients if CHTYPE=NONE

No input.

Hydrodynamic force coefficients if CHTYPE=MORI

No input.

Hydrodynamic force coefficients if CHTYPE=TVIV

Restricted option. Under implementation.

Time domain VIV load options and coefficients, 2 or 3 input lines. If a number is found instead of CHTVIV, the input is read in the old input format.

CHTVIV NMEM CHH

  • CHTVIV: character(8): Time domain VIV load option

    • = CF: Cross-flow VIV loads only

    • = CFIL: Cross-flow and in-line VIV loads calculated independently

    • = IL: In-line VIV loads only

  • NMEM: integer > 0, default: 500: Number of time steps used in calculation of standard deviation

  • CHH: real >= 0, default: 0.0: Higher harmonic load coefficient (nondimensional)

Cross-flow VIV load coefficients. The following input line is given if CHTVIV is CF or CFIL:

CV FNULL FMIN FMAX

  • CV: real >= 0: Vortex shedding force coefficient for the (instantaneous) cross-flow load term (nondimensional)

  • FNULL: real > 0: Natural cross-flow vortex shedding frequency (nondimensional)

  • FMIN: real > 0: Minimum cross-flow vortex shedding frequency (nondimensional)

  • FMAX: real > FMIN: Maximum cross-flow vortex shedding frequency (nondimensional)

Independently calculated in-line load coefficients. The following input line is given if CHTVIV is CFIL or `IL:

CVIL FNULIL FMINIL FMAXIL

  • CVIL: real >= 0: Vortex shedding force coefficient for the (instantaneous) in-line load term (nondimensional)

  • FNULIL: real > 0: Natural in-line vortex shedding frequency (nondimensional)

  • FMINIL: real > 0: Minimum in-line vortex shedding frequency (nondimensional)

  • FMAXIL: real > FMINIL: Maximum in-line vortex shedding frequency (nondimensional)

Specifying CVIL, ALPHIL and CHH as zero will give excitation only in the updated cross-flow direction

Time domain VIV parameters for pure CF are shown in a Table with recommended values.

1.4. Initial cross-section parameters, one input line

DESJS THSJS

  • DESJS: real: External diameter at first end of first conical section in stress joint \(\mathrm {[L]}\)

  • THSJS: real: Wall thickness at first end of first conical section in stress joint \(\mathrm {[L]}\)

1.5. Parameters to define the conical stress joint sections, NSJSEC input lines

NSJS DESJ THSJ SJSL NELSJ EMOD RHO

  • NSJS: integer: Stress joint section number. To be given in increasing order starting with #1

  • DESJ: real: External diameter at second end of the section \(\mathrm {[L]}\)

  • THSJ: real: Wall thickness at second end of the section \(\mathrm {[L]}\)

  • SJSL: real: Length of the section \(\mathrm {[L]}\)

  • NELSJ: integer: Number of segments within the section

  • EMOD: real: Young’s modulus of elasticity \(\mathrm {[F/L^2]}\)

  • RHO: real: Density of pipe material \(\mathrm {[M/L^3]}\)

Each segment will consist of one element. CRS0 cross-sections will be generated automatically for each segment in the stress joint.

um ii fig50
Figure 1. Stress joint description