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How to obtain turbulent K.E. from DNS data?

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Old   November 28, 2003, 07:35
Default How to obtain turbulent K.E. from DNS data?
  #1
Boying Lin
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There're mean and fluctuating velocities,Reynolds stress budgets,but not turbulent kinetic energy.Should I simply square each fluctuating component and sum up them?
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Old   November 29, 2003, 00:15
Default Re: How to obtain turbulent K.E. from DNS data?
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Subhra
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If you have 9 budgets for 9 reynolds stress components u can add the budgets for diagonal Re-stresses namely the (u^2) bar, (v^2)bar and (w^2)bar budgets and divide by 2 to get turbulent k.e. budget... sorry if it is not that simple...

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Old   November 29, 2003, 07:51
Default Re: How to obtain turbulent K.E. from DNS data?
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Boying Lin
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But what I want is the distribution of k.
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Old   November 29, 2003, 08:10
Default Re: How to obtain turbulent K.E. from DNS data?
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Boying Lin
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Oh!I'm sorry!It's rms velocities,not fluctuating velocities.So I can simply square each component and sum up them.
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Old   December 15, 2003, 08:18
Default Re: How to obtain turbulent K.E. from DNS data?
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Jonas Bredberg
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Hi,

k=(uu+vv+ww)/2

DNS-data commonly gives you the value of each Reynolds stress and hence you just adds the normal-components and divide by two. Check that you have the Reynolds stress (e.g. uu) and not the fluctuating velocity (e.g. u).

/Jonas
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Old   December 16, 2003, 06:40
Default Re: How to obtain turbulent K.E. from DNS data?
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Boying Lin
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Ah!I got it.Thank you, Jonas!
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