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A question about UEqn.H in smallpoolfire2D

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Old   August 14, 2013, 01:12
Default A question about UEqn.H in smallpoolfire2D
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赵庆良
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Hi Foamers:
According to the following codes in UEqn.H:
fvVectorMatrix UEqn
(
fvm::ddt(rho, U)
+ fvm::div(phi, U)
+ turbulence->divDevRhoReff(U)
==
parcels.SU(U)
);
UEqn.relax();
if (pimple.momentumPredictor())
{
solve
(
UEqn
==
fvc::reconstruct
(
(
- ghf*fvc::snGrad(rho)
- fvc::snGrad(p_rgh)
)*mesh.magSf()
)
);
}
The momentum equation that the smallpoolFire2D sloves is
fvm::ddt(rho, U)+ fvm::div(phi, U)+ turbulence->divDevRhoReff(U)
==parcels.SU(U)+fvc::reconstruct((- ghf*fvc::snGrad(rho)- fvc::snGrad(p_rgh))*mesh.magSf()).
I understand all term in the equation except the term of "parcels.SU(U)".
In many example in OF,there is no term of "parcels.SU(U)" in UEqn.H.How can understand the term?Is there any theory about the term?
please some foamers know tell me.I really need help!
Thank you!
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Old   August 14, 2013, 14:33
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Matvej Kraposhin
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I'm not an expert in the fire simulation, but from the source which you provided (fireFoam) i understand that term parcels.SU(U) is an explicit contribution to the moment conservation of the fluid from parcels.

This parcels (i guess!!!) are moving in the main fluid and term parcels.SU(U) used to include their drag and other forces.

To obtain more information, you have to make a more deep look at the fireFoam solver source code
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Old   August 15, 2013, 22:16
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Thank you for your reply,now I make a more deep look at the fireFoam solver first!
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