external flow fft
 

ı am beginner of cfd and I am planing to do transient analsysis in external flow to get in a surface pressure result and then I would like to do FFT for this result to get pressure in frequency domain.

1) I can not figure out what is time step size and number of time step to compensate 400-10.000 Hz pressure specturum for unsteady analysis ?

2) is there any example to get fft conversion in cfd analysis ?

regards

ozer