[manafaero]

hi

I want to do a FFT of the spatial data, i.e. FFT for the data extracted over a line, This FFT is then computed for each time step in OpenFOAM. Can anybody help me with the same.

Thanking you

[Swift]

Hi Manaf,

Does an FFT of spatial data make sense? What frequency would you expect to get? The mesh size? What are you trying to achieve?

I would think that you need to record the data at a point verses time and take an FFT of that.

If you really want to do as you describe, you should be able to create a line source in paraview and export that for all times to a spreadsheet or csv file. You would then need to use python or similar to reconstruct the data into a format that you could take an FFT.

I don't think there a native way to do FFT in Openfoam.

Good luck.
Thomas

[manafaero]

Thank you sir

[gigilentini8]

Thomas you are wrong!

there a nice little FFT library in OpenFOAM for cartesian meshes

https://cpp.openfoam.org/dev/dir_afc...e9c4c8c41.html

Originally Posted by Swift

Hi Manaf,

Does an FFT of spatial data make sense? What frequency would you expect to get? The mesh size? What are you trying to achieve?

I would think that you need to record the data at a point verses time and take an FFT of that.

If you really want to do as you describe, you should be able to create a line source in paraview and export that for all times to a spreadsheet or csv file. You would then need to use python or similar to reconstruct the data into a format that you could take an FFT.

I don't think there a native way to do FFT in Openfoam.

Good luck.
Thomas

[HPE]

I increase the bid:

FFTW is a part of OpenFOAM. You can use FFTW inside OpenFOAM, therefore.

PS: at least the com version.

[PawanSrinivasaMurthy]

Hello, is it possible to use just the fft.C file without compiling it as an openFOAM solver? I wanted to check if it works for my case before I use it in my solver.