Individual pitch control for BLADED-style controllers

An option to select collective or individual pitch control has been added for BLADED-style external controllers. This sets entry 28 in the avrSWAP array for communication with the controller to 0 (collective pitch control) or 1 (individual pitch control).

Accelerations exported to external wind turbine controller

The original acceleration signals exported are a result of the time integration algorithm, and may not represent values the user expects. For example, using the Newmark procedure with beta = 0.25, acceleration values correspond to an average value during each time step.

To improve this, a new option to calculate the accelerations from displacements is added.

Absolute convergence criterion

If the current is set to zero or a very low value, the static loading process in may not succeed due to the relative convergence criterion. To address this, an absolute convergence limit has been introduced in addition to the displacement and energy convergence norms.

The absolute convergence limit is determined based on an estimated equivalent diameter multiplied by a small factor.

Automatic static loading sequence in RIFLEX

A new option to automatically create loading sequence is added to static calculation. The model will be inspected and the required load groups will be constructed. It is also possibe to use "Create initial loading sequence" action to populate the table manually to use as a start.

Rope/Wire cross section

A new wizard is added in the new menu for cross sections to help creating Axisymmetric cross sections representing steel wire or nylon/polyester rope.

T-N fatigue calculation

Fatigue damage may be calculated from tension time series and a T-N curve. The functionality is available for RIFLEX beam and bar elements using the forces stored in the “OUTMOD” format.

Include slug loads from angles between element ends

Loads from the internal fluid are applied if a slug is specified or varying internal content is read from a flow import file.

Previously, only the change in flow direction given by curvature over the individual elements have given loads on the system. For example, a main riser line consisting of two lines with an angle between their stress-free orientations, would not have had a load contribution from this angle.

The loads from the angles between the element ends are now included. For each element, nodal loads corresponding to half of the angle between the element ends and the neighbouring element ends are applied.

The change will normally be negligible unless there are angles between neighbouring element in the stress-free configuration.

Initial configuration for RIFLEX Task

When creating a new RIFLEX task, two new options are now added to the wizard: Steel catenary riser and Lazy wave. These options are also available in the slender system editor (Create line action)

Super Nodes Folder Editor

The editor showing all Super Nodes in the same view has been improved. Global initial and static position is shown for all in an overview, and the separate Initial and Static views are filtered based on the relevance of the Super node

S-N curves update

Predefined S-N curves updated to latest DNV-RP-C203 (Edition October 2024)

Visualize grid for the first plane of "fluctuating three component" turbulence.

If the Initial environment is selected and configured with "fluctuating three component" wind, a grid representing the front (most downstream) plane of a turbulence box will be visualized in the 3D View of the relevant task. The grid is dynamically updated based on user input of Wind field size, -domain position and -domain size, making it easier to place and orient the box correctly in an environment.

Reverse order of encounter for "fluctuating three component" turbulence (Mann turbulence boxes)

Similar to several other simulation tools, SIMO/RIFLEX had a long-standing error where Mann turbulence boxes were read/applied in the wrong order.

Based on the clarification published by DTU Wind Energy (https://tools.windenergy.dtu.dk/hawc2/downloads/13.1.0/Turbulence_box_wrong_direction.pdf), this error has now been corrected. Thus, the first turbulence plane in a Mann turbulence file, is now the most upwind turbulence plane, and (nominally) last to reach the turbine.

From this release, the correct behaviour is applied by default. This implies that results using this wind type and the latest release of SIMA/SIMO/RIFLEX, will differ from results obtained using previous versions. To allow users to reproduce previous results, a new Reverse Box check-box has been added to SIMA (setting irev to 1 in SIMO/RIFLEX WIND SPECIFICATION, defaults to 0) to re-enable the incorrect legacy behaviour.

Overview of the signals in the controller log file

A table with an overview of the contents in the wind turbine log file printed by SIMA is added to the user manual.

IEA 22 MW reference wind turbine

The IEA 22 MW reference wind turbine is available as an example

Matrix plot improvements

It is now possible to view multiple matrix plots together (mpf-files in the results)

How-to model wind turbine

Recommended practice for modelling a wind turbine added to the how-to section of the user manual

Matrix storage format

The default matrix storage is changed to AUTOMATIC. The matrix storage format will be automatically set to Sparse or Skyline in the static analysis depending on the finite element model.

Ramping of wind velocity

The wind velocity can now be ramped using a predefined clutch. The wind will be gradually scaled from an initial scaling value up to the full value at time RAMP_DURATION.

Deactivate current in static parameter variation

If current is specified but not activated in the static loading sequence, the current will be activated if static parameter variation is specified. The current will then be added in the first load step.

An new option to deactivate the current is added.

Illustration of static loading groups

Illustration of common configuration and suggested order of static loads are added in the user manual

Local Element Axis now part of Line

Local Element Axes are moved into line object.

Marine growth scaling for individual lines

The scaling factor for marine growth can now be specified for individual lines in addition to an overall scaling factor. This will allow the user to switch between no marine growth, partly accumulated marine growth and fully developed marine growth on selected lines.

Read current profile from file

The current profile can now be defined in a separate file and given as input.

User defined element type

The user defined elements can now be connected to either end one, end two or both ends of the reference element.

Currently, only single node elements are available. The element is primarily intended for modelling seafloor contact, anchor modelling, additional loads or other type of contact problems but may be used for other purposes.

Tension and curvature capacity check

Perform a capacity check for a combination of curvature and tension. The capacity is expressed by a utilization factor.

Mooring line capacity check

Mooring line capacity check is added according to the DNV Offshore Standard Position mooring, DNV-OS-E301 Capacity Check (2021).

Static convergence information

Information about the static convergence is now written to the <*>_stamod.mpf file. The following information is now available:

Correction to dynamic winching out

A longstanding error has been corrected for winching out in dynamic analysis for * winch with fixed position * winch attached to a RIFLEX vessel without a motion transfer function

Contact radius for stress-joint

The inner and outer contact radius was set 0 for stress joint. This is now changed and set to

Prebent linetype and mass summary fixed

Mass summary in Line Type editor was wrong for segments with offsets

Time interval for fatigue calculations

An error will now be given if the specified start of the interval for fatigue calculation is larger than the simulation length.

Corrected the calculation of stored time step number from time. This could previously be incorrect by one stored time step.

Error for slug flow when not defined for the first line(s) in the system

For AR-systems, the specified slug is applied to the first main riser line (MRL) in the system. The code assumed that the lines in this MRL were the first lines in the system, and in the same order that they were defined.

The error would normally cause a program exception and termination.

Longstanding error

Winch out dynamic analysis - incorrect element length

When winching out, the stress free length of released elements become different from original stress free length.

Nodal body attached to a segment with loadtype None

A nodal body attached to a segment with loadtype None will not get any hydrodynamic load .

Work around

Nodal body

A nodal body cannot be attached to a segment with loadtype HNET or Morison partly submerged .

Work around

Linear drag coefficients not applied for partly submerged load type

Specified Linear drag coefficients will be ignored in the analyses for elements with the partly submerged load type.

SIMA now supports difference frequency QTFs stored on an external file, corresponding to a new QTF force implementation in SIMO

This feature reduce drastically the size of the SIMA workspace for models containing large amounts of QTF data. The external QTF file will be created automatically at SIF import, or can be exported from an existing model. The QTF file is used directly by SIMO during simulation, reducing also the overhead related to data exchange between SIMA and SIMO. The QTF on the external file can be read by SIMA for plotting and the effect of current on the QTF can be included in the plot. The new SIMO implementation generates time series of QTF force more efficiently. An "on-demand" pre-generation strategy is used, which means that pregeneration for body headings never encountered during the simulation will be avoided. The new model can expand wave headings based on body symmetry. The mean wave force is also included in static analysis (unlike the previous QTF model). Now it is possible to use sum- and difference frequency QTFs at the same time by using the new difference frequency model in combination with the existing sum-frequency model.

New hydrostatic force model containing submerged volume and center of bouyancy

A new hydrostatic force model have been added which explicitly includes the mean buoyancy force in the centre of buoyancy. The change in buoyancy due to non-zero position and rotation is included via linear restoring coefficients. When the new hydrostatics model is used, the gravity force will always be included, regardless of the "Apply gravity force" flag.

Drift motion file in WASIM export

WASIM result export has been expanded and now also include a drift motion file which include the body position used for computation of wave kinematics.

Read current profile from file

The current profile can now be defined in a separate file and given as input.

Various runtime errors

Several needless errors from simulations have been resolved in this release.

Improved copy possibilites for condition run command

It is now possible to copy selected files to a given destination after a condition run using the condtion run command.

Tools - Advanced - Run SIMA batch command then right click to create new run condition command to test the functionality

Automatic rotation point in 3D

It is no longer necessary to set rotation point manually in 3D view. This is automatically set when triggering rotation.

Fixed delete issues in post processor

Delete operation in an empty spot in postprocessor or workflow diagram no longer deletes the entire postprocessor or workflow

Fixed copy values in plot

Fixed copy values in plots such as wave spectrum in the environment editor.

Additional structural damping from file

The structural damping may be applied using either geometric and material stiffness or only the material stiffness.