|September 27, 2010, 10:37||
BuoyantBoussinesq(Pimple/Piso)Foam, changed equation from OF 1.6 to 1.7 ???
Join Date: Jun 2010
Location: Erlangen, Germany
Posts: 3Rep Power: 7
one question regarding the changes from OF 1.6 to 1.7 in the buoyantBoussinesq(Piso/Pimple)Foam solver. I think the implementation of splitting the pressure according to p = p_rgh + rho*g.x is not fully correct.
The pressure equation in OF 1.7 seems OK, since in the Rhie-Chow formulation the contributions from the static pressure cancel and we are left with:
phi = (fvc::interpolate(U) & mesh.Sf()) + fvc::ddtPhiCorr(rUA, U, phi); surfaceScalarField buoyancyPhi = rUAf*ghf*fvc::snGrad(rhok)*mesh.magSf(); phi -= buoyancyPhi;
surfaceScalarField phiU ( (fvc::interpolate(U) & mesh.Sf()) + fvc::ddtPhiCorr(rUA, U, phi) ); phi = phiU + rUAf*fvc::interpolate(rhok)*(g & mesh.Sf());
In contrast, in the momentum equation the term for the buoyancy ( and gravity) force has changed from (OF 1.6)
fvc::reconstruct( ... fvc::interpolate(rhok)*(g & mesh.Sf()) ...)
fvc::reconstruct( ... - ghf*fvc::snGrad(rhok)*mesh.magSf() ...)
Is this really a bug or do I miss some point? Thanks for any comment...
In the meantime I am pretty sure this is indeed a bug and I submitted a bugreport.
Problem is solved. This bug was fixed a few days ago in the git repository.
Last edited by myself; October 7, 2010 at 11:19.
|July 28, 2011, 05:21||
Join Date: Aug 2010
Posts: 161Rep Power: 7
can someone explain me why OF1.7 still uses
fvc::interpolate(rhok)*(g & mesh.Sf())
I do not understand why the gradient of the densitiy is used while in the equations I find in literature it has to be just the densitiy multiplied with the constant g.
Can someone help me? Is this still a bug or do I overlook something?
|September 14, 2011, 02:03||
You wrote that the term in OF17 was formulated with an error, am I correct?
But still if i look OF171 (Ubuntu package installed via apt-get):
UEqn == fvc::reconstruct ( ( - ghf*fvc::snGrad(rhok) - fvc::snGrad(p_rgh) )*mesh.magSf() )
Dr. Alexander VAKHRUSHEV
Christian Doppler Laboratory for "Advanced Process Simulation of
Solidification and Melting"
Simulation and Modelling of Metallurgical Processes
Department of Metallurgy
University of Leoben
A - 8700 Leoben
Österreich / Austria
Tel.: +43 3842 - 402 - 3125
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