[MATLAB] FFT of Velocity Time Series
 

Hello all,

I'm looking to create a frequency spectra of energy to show that I am in fact resolving down to the Kolmogorov scales. I have saved velocity values at each time step, but from there I'm sort of confused. I know how to do a fast fourier transform in matlab, but am really not sure how I go about creating the plot of E vs. omega (frequency). From what I understand, I need to do the FFT, calculate the magnitude of the coefficients I receive, and then I square this to get energy? From there, how do I plot this again my frequency?

Any help would be appreciated, I've never really used matlab before and I've also never done an FFT.

Thanks in advance,
Jeff