I am a PhD student working on coupling FAST with our in-house CFD code. As suggested in an earlier post, the SOWFA tool (SOWFA version of the FAST) is used for this purpose.
I am using the input files for the NREL 5MW provided in the SOWFA archive.
The induction factor model in the Aerodyn input file is given as ‘NONE’. Is this what we should use when coupled with a CFD code? Is this because the wind velocities are being provided right at the blade nodes and so induction effects are already taken into account by the CFD?
Also, when using ‘NONE’ as the value of the induction factor, the rotor torque reported in the output file is considerably higher than what it should be? Could you please shed some light on this.
Thank you very much for your help in this matter.
In SOWFA, the induction is computed within the OpenFOAM CFD code, which is why “NONE” is selected within AeroDyn. This is achieved through the coupling scheme, whereby the wind velocities are sent from OpenFOAM to AeroDyn and the aerodynamic loads (lift and drag) are sent from AeroDyn to OpenFOAM at each blade analysis node at each time step. The rotor torque output should not be “considerably higher” than normal.
I’m not sure if the couping to your CFD code works the same way.
Thank you for the quick response and sorry for getting back so late.
I have coupled the SOWFA version of FAST with our CFD code in exactly the same way as has been done with OpenFoam.
I had a bug and now, things are working fine.
Thank you very much for your help.
I did some test runs with the NREL 5MW model and constant wind speed (the IndModel option is set to “NONE”).
Unfortunately the turbine always speeds up to rated speed (12.1 rpm) no matter what wind speed I use.
I dont have a fixed rotor speed set and if IndModel is set to SWIRL everything works as expected.
Does anyone have an idea what the problem could be?
[UPDATE] I just checked my old Windows installation and it seems to work. The Linux-BladedDLL interface that I use somehow seems to be broken or I have somewhere an error in my input.