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mut and alphat & compressible flow

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Old   September 17, 2013, 07:41
Default mut and alphat & compressible flow
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Sasan Ghomi
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Hi foamers ,

I have a question about setting mut and alphat file in the 0 directory .

I checked rhopimpleFoam tutorial . In this case all values of mut and alphat on the walls are 0 .

type mutwallFunction;
------> for mut
value uniform 0;

type alphatwallFunction;
------> for alphat
value uniform 0;

Also I checked kEpsilon.C in this source code I found a formula for calculating mut and alphat .


mut_ = Cmu_*rho_*sqr(k_)/epsilon_;
alphat_ = mut_/Prt_;

I want to create a case by coldEngineFoam . So I should set mut and alphat file and I am confusing about setting these files.
Please anybody guide me. I should set uniform 0 for them or I should calculate them by using their formula . Why in the tutorial the values have set uniform 0 ??

I appreciate any help from you.
Thanks and best regards,
Sasan.


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Old   September 17, 2013, 12:54
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Nima Sam
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as much as i know , when you are using wall function, the value is place holder! so that value is not important and the value of variable will be calculated based upon correlation
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Old   September 17, 2013, 14:42
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Sasan Ghomi
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Dr.Sam
Thank you very much for your reply.
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