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Old   June 23, 2005, 05:48
Default Hello, I have a question on t
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Alberto Passalacqua
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Hello,
I have a question on the implementation of the eulerian model in bubbleFoam.

Why the alpha equation has been implemented as:

fvScalarMatrix alphaEqn
(
fvm::ddt(alpha)
+ fvm::div(phi, alpha, scheme)
+ fvm::div(-fvc::flux(-phir, beta, scheme), alpha, scheme)
);

and not as

fvScalarMatrix alphaEqn
(
fvm::ddt(alpha)
+ fvm::div(phia, alpha, scheme)
);

Best regards,
Alberto
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Old   June 23, 2005, 05:51
Default To maintain boundedness of alp
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To maintain boundedness of alpha at the 1 limit as well as the 0 limit.
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Old   June 23, 2005, 07:27
Default Thank you Henry. Alberto
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Thank you Henry.

Alberto
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Old   August 24, 2005, 02:55
Default Could anyone explain the deffe
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Sang Yong Lee
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Could anyone explain the defference between,
fvm::ddt(rho,e), and rho*fvm::ddt(e) ?
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Old   August 24, 2005, 03:16
Default Does rho vary with time?
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Does rho vary with time?
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Old   August 24, 2005, 03:38
Default Yes, rho varies with time.
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Yes, rho varies with time.
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Old   August 24, 2005, 03:46
Default In that case they are clearly
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In that case they are clearly different, the first is the rate of change of rho*e and the second is rho* the rate of change of e, wasn't that obvious?
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Old   August 24, 2005, 04:13
Default Yes, it is obvious. Could you
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Yes, it is obvious.
Could you tell me the correct expression among the following ones;

fvm::ddt(rho,e)=( (rho)^^(n+1)*e^^(n+1) - (rho)^^n*e^^n )/dt or
fvm::ddt(rho,e)=( (rho)^^n*e^^(n+1) - (rho)^^n*e^^n )/dt

Or, if both are not correct, give me correct one please .
Thank you
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Old   August 24, 2005, 04:20
Default The first expression correspon
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The first expression corresponds to an Euler-implicit discretisation of fvm::ddt(rho,e) and the second is clearly equivalent to an Euler-implicit discretisation of rho*fvm::ddt(e).

If you need to know these details you should look at the source code, it is all there ready and waiting for you, all you have to do is load it into an editor. The files you need to look at for implicit temporal discretisation are all in OpenFOAM-1.2/src/OpenFOAM/finiteVolume/ddtSchemes.
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Old   September 21, 2005, 01:33
Default Dr. Weller I am trying to imp
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Dr. Weller
I am trying to implement energy equation in bubbleFoam. I have problems with the disapprearing phases. As I reviewed your technical report, TR/HGW/02, Derivation...., I got an idea that your phase intensive momentum equation approach might help me. Could you give me some comments on using phase intensive energy equation instead of using the energy equation in conservative form.
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