Orcina news

We have just released a minor upgrade to OrcaFlex, version 11.0b. Version 11.0b introduces some minor new functionality and fixes a number of bugs. Full details of the changes are described in the documentation:

• OrcaFlex
• OrcaWave

The bug fixes are particularly important for OrcaWave and so we especially recommend that you install this upgrade if you are using OrcaWave.

A patch to upgrade from 11.0a to 11.0b can be downloaded here. The full installation program can also be downloaded from your Orcina download page. Please contact us if you do not have the link to your Orcina download page.

We have just released a minor upgrade, version 10.3e, which introduces support for Python 3.8, and fixes a number of bugs. Full details of the changes are described in the documentation. We recommend that users of 10.3 upgrade to 10.3e.

A patch to upgrade from earlier versions of 10.3 can be downloaded here. The full installation program can also be downloaded from your download page. Please contact us if you do not have the link to your download page.

Some OrcaFlex users have reported program crashes when trying to execute embedded Python code. These crashes causes OrcaFlex to close without reporting any error message.

If Python scripts are used for OrcaFlex post calculation actions, user defined results or external functions, OrcaFlex must launch a Python interpreter to run the input scripts. We refer to this mode of operation as running embedded Python.

Some clients make use of Anaconda products as their installed Python. However, Anaconda’s packaging of Python 3.7 fails to initialise when OrcaFlex wants to run some embedded Python code, leading to a program crash.

This issue can usually be resolved by creating a new environment variable, PYTHONHOME, and setting its value to your Anaconda Python installation directory.

You can find the environment variables by starting with the System Properties window:

and add PYTHONHOME by selecting New… from the User Environment Variables list:

OrcaFlex version 11.0 provides the Python home directory information to embedded Python automatically. Updating OrcaFlex to version 11.0 will therefore resolve the issue without requiring you to modify environment variables.

We would like to thank all of our users who brought the problem to our attention, and also helped us to find the solution!

We are very pleased to announce the release of OrcaFlex version 11.0. The software was finalised and built on 28^th November. All clients with up-to-date MUS contracts should receive, by e-mail, instructions on how to download the new version.

Version 11.0 introduces much new functionality, including:

• Diffraction analysis
• Enhanced wind turbine modelling
• Wind drag loading for 6D buoys
• Enhanced wind specification
• Disturbed sea state results for vessels
• New results variables
• Hysteretic constraint stiffness
• Enhancements for 3D views
• Software licensing

These are the most significant developments, in our opinion. As always there are more enhancements that are not listed here. All new features are fully documented in the what’s new topic for 11.0.

Continue reading “OrcaFlex 11.0 released”

OrcaFlex 10.3 introduced the turbine object, used to model horizontal axis wind turbines.

A key issue for wind turbine analysis is the modelling of the generator and blade control systems. Because these control systems are typically proprietary, OrcaFlex does not offer any built-in control system functionality. Rather, the user must specify the control systems through external functions.

When we released 10.3d, we updated the documentation to include some example external function controllers. The pertinent help topics are:

• Turbine data: Generator
• Turbine data: Blades

A guide to using external functions to model turbine controllers is available at https://github.com/Orcina-Ltd/turbine-controllers. This includes example Python controllers and an example of using external functions to wrap a Bladed style control DLL.

Other useful sources of information for turbine modelling:

• K01 Floating wind turbine example
• Turbine validation

We have just released a minor upgrade, version 10.3d, which fixes a number of bugs. Full details of the changes are described here. We recommend that users of 10.3 upgrade to 10.3d.

A patch to upgrade from earlier versions of 10.3 can be downloaded here. The full installation program can also be downloaded from your download page. Please contact us if you do not have the link to your download page.

Following the introduction of the turbine model object in version 10.3 we have now produced a report which details the validation performed on the turbine against documented industry studies.

The validation study considers the National Renewable Energy Laboratory (NREL) offshore 5-MW baseline wind turbine, which is
recognised as an industry-standard reference turbine system.

Two separate turbine systems have been modelled and subjected to detailed analysis in OrcaFlex:

• A land-based wind turbine system.
• A floating wind turbine system – based on the OC3 Hywind system.

Analysis of the land-based scenario was considered to facilitate basic validation of the turbine response determined via OrcaFlex. Detailed analysis of the OC3 Hywind system was then considered to help validate the behaviour of a fully-coupled floating wind turbine system in OrcaFlex.

Results were compared to those from other wind turbine simulation tools; namely FAST, MSC.ADAMS, Bladed and HAWC2.

Overall, OrcaFlex has been shown to accurately capture the aerodynamic and hydrodynamic loading on the considered turbine systems. Close agreement was generally observed between the OrcaFlex results and those available from the other simulation tools – particularly with respect to the calculated turbine rotor response.

The full report is available alongside previously published OrcaFlex validation cases on the validation page here.

We have just released a minor upgrade, version 10.3c, which fixes a number of bugs. Full details of the changes are described here. We recommend that users of 10.3 upgrade to 10.3c.

A patch to upgrade from 10.3a or 10.3b to 10.3c can be downloaded here. The full installation program can also be downloaded from your download page. Please contact us if you do not have the link to your download page.

We have just released a minor upgrade to OrcaFlex, version 10.3b. Version 10.3b introduces some minor new functionality and fixes a number of bugs. Full details of the changes are described here.

A patch to upgrade from 10.3a to 10.3b can be downloaded here. The full installation program can also be downloaded from your download page. Please contact us if you do not have the link to your download page.