# Energy Spectrum

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 June 12, 2003, 08:37 Energy Spectrum #1 Emad Khalifa Guest   Posts: n/a I'm simulating fully developed turbulent pipe flow. I need to calculate the energy spectrum. I used MATLAB with its FFT function (fast fourier transform) to compute the energy spectrum. The trend of the energy spectrum is good but it is in an oscillating form. Does any body have an idea to compute the energy spectrum ? Thank you

 June 12, 2003, 08:52 Re: Energy Spectrum #2 Tom Guest   Posts: n/a Hi, Perhaps you can try to divide the wave number range into small intervals.Then integrate the energy of all energy components with a wave number in a certain interval and scale it with the size of the bin. This will give you a kind of average and will smooth out the oscilations. Don't take the bins too large because then you smooth out the complete spectrum. Tom

 June 19, 2003, 08:29 Re: Energy Spectrum #3 Emad Khalifa Guest   Posts: n/a I did not understand what you exactly mean. Would you please explain in detail ? Thank you

 June 30, 2003, 16:03 Re: Energy Spectrum #4 hall Guest   Posts: n/a the spectrum is a kind of averaging. If it is oscillation, enlarge the range of averaging. In spectral space, it means enlarge the interval between modes. For example if the interval is -0.1 < k < 0.1 before, now you use -0.5 < k < 0.5. ( it is just an example, don't use it directly) Mohmd likes this.