Learning Forum

[KKC]

Hi,

Assume the flow is incompressible while answering.

I want to know what does pressure spectra re and pressure spectra im quantities mean under acoustics.

Does these quantities represent the acoustic pressure spectra or they refer to hydrodynamic pressure spectra.

If acoustic pressure spectra, how do these values are generated.

As *.asd file record, the total pressure on the source selected, which is an output from the flow. We perform FFT on this data (Converting time-domain to frequency and smoothes the data using a window). How does that become an acoustic quantity? Does something else happen while performing FFT?

[Marco Coderoni]

Hello,
The pressure spectrum re and im are the real and the imaginary parts of the complex Fourier amplitudes.
Depending on where the surface source is located you may see only acoustic effects or a mix of hydrodynamic and acoustic effects. It is up to you to understand what kind of pressure is acting on the acoustic sources you selected, based on the physics of your problem. The FFT is directly applied to the signal you are providing.
You can refer to "23.2.6. FFT of Acoustic Sources: Band Analysis and Export of Surface Pressure Spectra" of the User's Guide for more information.

Hope this helps

[esha]

Hi, I am trying to plot acoustic signal but I have never done it. Can you please explain how may I do it. I have .asd files. But next I am lost. your help will be highly appreciate. Thank you !