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-   -   FFT problem (http://www.cfd-online.com/Forums/fluent/46187-fft-problem.html)

rav_aero October 1, 2007 02:49

FFT problem
 
hey can anybdy tell me how to do FFT(fast fourier transform). my data consists of pressure and time. now i need to do FFT to find the dominant frequency. in fluent its written that i need to give the input signal file. but how do i generate the signal file? is there any other way by which i can do it?

thank u.

Mat W October 1, 2007 12:14

Re: FFT problem
 
this has been covered in this forum several times before, do a search. in short, you need to create an output file which has two columns - one for time and one for the time dependent variable. This can easily be done by going into Solve>Monitor>surface and selecting the time dependent variable you want to monitor (in your case some measurement of pressure). The file will update after each time step. Once you are happy you have enough time steps to represent the time dependent characteristics, load the file into the FFT panel.

rav_aero October 2, 2007 23:49

Re: FFT problem
 
Thank u very much Mat..


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