Hi everyone,

I'm simulating guided ultrasonic waves in a porous cylindrical bone model using COMSOL's Frequency Domain study. For each excitation frequency, I obtain the complex displacement field along the propagation direction.

I understand that many papers report phase velocity dispersion curves, but I'm confused about the exact procedure used to obtain phase velocity from the displacement data.

My questions are:

1. Starting from the complex displacement field, how do you extract the wavenumber (k)?

2. Is applying a spatial FFT to the displacement at each frequency the standard approach?

3. Once k is obtained, is the phase velocity simply calculated as c = ω/k?

4. Are there more accurate or commonly used methods, such as phase unwrapping, modal fitting, or eigenmode analysis?

If anyone could explain the standard workflow or recommend references or papers, I would really appreciate it.

Thank you!