Dear Bastian,
If I read this correctly, you want to produce wind inflow (turbulence) files that can be read in a FAST/AeroDyn simulation. in FAST, these files are actually read by a module called InflowWind, which accepts several different formats (or allows you to create your own format in a UserWind routine, assuming you code the subroutine to read the format you created.)
Most likely, you would create binary full-field turbulece files, such as the ones TurbSim generates (in a y-z plane at constant time intervals; with a .bts extension). The format is described in appendix D of the TurbSim User’s Guide. I also have pulled out the TurbSim code (Fortran) that creates the wind files, and I made some modifications so that it should work outside TurbSim; you can find it here: [url]National Wind Technology Center's Information Portal | Wind Research | NREL You will need to use the NWTC Library to compile/use it. I’ve tried to make all the variables you’ll need to define as inputs. Note that TurbSim’s V array is only 3 dimensions: dimension 1 is time, dimension 2 is grid point, and dimension 3 is velocity component (U,V,W – see figure 3 in the TurbSim User’s Guide). The top of the routine indicates the numbering convention of the grid points (2nd component).
TurbSim also produces a Bladed-style FF binary file (.wnd, with a corresponding .sum file). This format is described in appendix E in the user’s guide; you can also read this post for help in generating them: binary .wnd specification
You can use the InflowWind module’s sample driver/test programs (one in Matlab, the other in Fortran) to verify that the files are generated correctly.