Ability to Use Tip Loss Correction Feature when using C++ API with WakeMod = 0

[mchurchf]

When we run OpenFAST with its C++ API coupled with CFD codes, the actuator line/disk model naturally accounts for induction, so we set WakeMod = 0. However, with actuator disk, we still may want to use a tip-loss correction because actuator disks do not capture tip vortices and their downwash. Tip-loss corrections are only available with WakeMod = [1|2].

Is it possible to make the tip-loss corrections available even with WakeMod = 0. The velocities from CFD can be sent to AeroDyn, AeroDyn can calculate aerodynamic forces, and then the tip-loss factor can be applied to the resultant loads.

For now, I am correcting the velocities sent from CFD to OpenFAST as a work around, but it is not exactly the same as correcting the forces afterward. I could apply the correction within the CFD code, but the uncorrected forces will still be used in OpenFAST resulting in an over prediction of loads and torque, so it would be best to have the correction available in AeroDyn outside the BEM iteration loop.

I am willing to help out with this effort, so feel free to work with me.

Thanks,

Matt Churchfield

[andrew-platt]

@ebranlard, let's keep this in mind while restructuring AD15.