Calculation of wind loads on the floating platform


I am trying to simulate the response of a large low-ballasted semi-submersible floating wind turbine. A significant portion of the floater is above water-line. I would like to calculate the wind-loads on the platform and include this in the simulation of the whole system. Is it possible to use aerodyn for the calculation of the wind loads on the platform ? If not, I can calculate it using other methods, is it possible to add these loads into openfast for calculation?

I would also like to calculate the loads due to currents and waves on the platform also separately and add it to openfast for calculation ? How can I do this in hydrodyn/openfast ?


Dear Rahul,

OpenFAST does not currently support the calculation of wind loads on the support structure except for the simple cylindrical tower drag model that is supported in AeroDyn v15. Perhaps the tower drag functionality of AeroDyn is suitable for your purpose? If not (e.g., because you want to calculate the aerodynamic load on multiple offset columns of a semisubmersible separately ), then you could modify the source code to calculate the loads you want. If you can calculate the applied loads in a preprocessing step (e.g., assuming the loads do not depend on structural motion), OpenFAST does support the ability to apply user-specified time series of point loads on the substructure through the structural control (StC) submodel of the ServoDyn module, which was released in OpenFAST v3.0 and would not require a change to the source code.

The HydroDyn module of OpenFAST can be used to calculate current and wave loads on floating semisubmersibles, so, I wouldn’t expect that you’d need to modify the source code or add your own user-specified point loads to model that.

Best regards,

Dear Jason,

Thank you so much for the help. The semisubmersible has multiple columns, so modifying the source code could be my option. I was thinking of calculating the wind loads using CFD and using it in the pre-processing stage. I hope this works.