for VIV (Vortex Induced Vibrations) you can assume a Strohal number of 0.2 and calculate the frequency. Run a transient simulation and count the number of vortices that shed. You can split the structure into two halfs (maybe quarters is better) and put goals for side load and downwind load and you can get a plot of the frequency vs. time as well. The program won't just spit out a frequency, well at least I haven't bothered to figure it out as it would likely require an FFT of the goal plot.
(was already running a transient simulation)
I just counted the vortex frame by frame in a 1 sec interval.