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position of body force on the momentum equation

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Old   September 23, 2014, 05:48
Default position of body force on the momentum equation
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lin
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Hi, I have a question on the position of the body force on the momentum equation. I have search the forum and find two different strategy:

1. It should be included in the Ueqn:

fvVectorMatrix UEqn ( fvm::ddt(U) + fvm::div(phi, U) - fvm::laplacian(nu, U) == F );

2: It should be included in the predictor step:

solve(UEqn ==F -fvc::grad(p));

Can any expert explain to me which one is correct?
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Old   September 26, 2014, 15:00
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Cyp
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You can do whatever you want as far as the PISO loop is consistent.

I mean, with the first option, you don't have to change anything in the algorithm (F is part of H).

For the second option, you have to modify the recontruction of the velocity from the pressure gradient to include F.

Both options leads to the same results.

Best,
Cyp
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Old   September 26, 2014, 22:31
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lin
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Thanks Cyp for your help.
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