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Old   November 12, 2012, 03:37
Default spanwise wavenumber calculation
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Muhammad Nadeem
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Hi All!
I am trying to compute spanwise wavenumber,kz for premultilpied spectra of streamwise veloity. I have spanwise length of Lz = 80 and node points, Nz = 256.

How can I calculate spanwise wavenumber,kz ?

Any help will be appriciated.
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Old   November 12, 2012, 06:32
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Filippo Maria Denaro
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Quote:
Originally Posted by Nadeem99 View Post
Hi All!
I am trying to compute spanwise wavenumber,kz for premultilpied spectra of streamwise veloity. I have spanwise length of Lz = 80 and node points, Nz = 256.

How can I calculate spanwise wavenumber,kz ?

Any help will be appriciated.
Are you talking about the maximum wavenumber? in general the frequency is linked to the wavenumbers:

fz = kz * Lz/2*pi

and the Nyquist frequency will be fx_max= Lz/(2*h) so than

1/(2*h)= kz_max /2*pi

kz_max = pi/h
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Old   November 12, 2012, 19:06
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Quote:
Originally Posted by FMDenaro View Post
Are you talking about the maximum wavenumber? in general the frequency is linked to the wavenumbers:

fz = kz * Lz/2*pi

and the Nyquist frequency will be fx_max= Lz/(2*h) so than

1/(2*h)= kz_max /2*pi

kz_max = pi/h

Thank you for your response. I want to calculate all wave numbers from minimum to maximum.

I want to conform one thing. Does 'h' refers to span-wise spacing?

Once again thanks for your response.
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Old   November 13, 2012, 04:00
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Originally Posted by Nadeem99 View Post
Thank you for your response. I want to calculate all wave numbers from minimum to maximum.

I want to conform one thing. Does 'h' refers to span-wise spacing?

Once again thanks for your response.

yes, h stands for dz in your case
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Old   November 13, 2012, 21:21
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Thanks a lot for your help.
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