Pablo,
My guess is that the differences you see in the FAST results using HH vs FF wind files representing the same flow field is because of the way AeroDyn calculates the “average disk velocity.” I have never liked the implementation AeroDyn uses, which takes
- the instantaneous wind speed and direction (not including gust speeds or any shear) from the HH files to calculate a sort of disk-averaged wind speed, or
- the FF advection speed for the U component, and 0 for the V and W components, which is the time-averaged hub-height wind speed (assuming the FF file has no wind direction)
So, it uses different averaging methods based on the type of wind file being used, and it can give very different results.
TurbSim does not have the ability to have time-varying HFlowAng. You could try to generate your own FF binary file to be read in AeroDyn/InflowWind, using formats/code descirbed in this post: Running FAST based on CFD turbulence fields.