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Energy spectrum in frequency

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Old   July 5, 2019, 07:59
Default Energy spectrum in frequency
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Ashish bhigah
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Hi I am trying to calculate the Energy spectrum, which is a concept usually applied to the wavenumber, but I want to calculate an energy spectrum in frequency.

In order to do that I calculated the autocorrelation function of 3 component of velocity in one point. I did the psd of the 3 component using the autocorrelation function not normalised.
Then I summed them and I divided these by two. So It is respected the fact that the mean value of turbulent kinetic energy is equal to the integral of the energy spectrum over the frequency.

do you think that this approach can be acceptable in order to calculate the energy spectrum in frequency?
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Old   July 5, 2019, 08:27
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Originally Posted by bhigahAshish View Post
Hi I am trying to calculate the Energy spectrum, which is a concept usually applied to the wavenumber, but I want to calculate an energy spectrum in frequency.

In order to do that I calculated the autocorrelation function of 3 component of velocity in one point. I did the psd of the 3 component using the autocorrelation function not normalised.
Then I summed them and I divided these by two. So It is respected the fact that the mean value of turbulent kinetic energy is equal to the integral of the energy spectrum over the frequency.

do you think that this approach can be acceptable in order to calculate the energy spectrum in frequency?



frequency and wavenumber is almost the same since k=n*2*pi/L
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Old   July 5, 2019, 08:33
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Yes, it is what I was thinking. So this approach can be acceptable?
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Old   July 7, 2019, 07:58
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Originally Posted by FMDenaro View Post
frequency and wavenumber is almost the same since k=n*2*pi/L

Thanks I was using this computation but I'm hesitant same reason for the OP if it's acceptable.
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Old   July 7, 2019, 10:54
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Thanks I was using this computation but I'm hesitant same reason for the OP if it's acceptable.
Hi, which reasons make you hesitant?
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