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-   -   SIMPLE for viscous NavierStokes (https://www.cfd-online.com/Forums/openfoam-solving/60288-simple-viscous-navierstokes.html)

almanstoetter July 11, 2005 13:44

I have modified the UEqn.H and
 
I have modified the UEqn.H and hEqn.h in buoyantSimpleFoam to represent steady laminar viscous Navier-Stokes:

volTensorField gradU = fvc::grad(U);
tmp<fvvectormatrix> UEqn
(
fvm::div(phi, U)
- fvm::Sp(fvc::div(phi),U)
- fvm::laplacian(2*mu+lambda, U)
);

UEqn().relax();

solve
(
UEqn() ==
fvc::div
(
mu*gradU.T()+lambda*I*tr(gradU)-(mu+lambda)*gradU
)
- fvc::grad(pd) + fvc::grad(rho)*gh
);

fvScalarMatrix hEqn
(
fvm::div(phi,h)
- fvm::Sp(fvc::div(phi), h)
- fvm::laplacian(k/Cp, h)
);

hEqn.relax();

solve
(
hEqn ==
fvc::div(phi/fvc::interpolate(rho)*fvc::interpolate(p))
- p*fvc::div(phi/fvc::interpolate(rho))
+ ((lambda*I*tr(gradU)+mu*(gradU+gradU.T())) && gradU)


Do UEqn.H() and UEqn.A() in pEqn.H still give the required diagonal and off-diagonal entries ? Has the field phi to be extended to use the SIMPLE algorithm in pEqn.H ?


Juergen

henry July 11, 2005 14:15

UEqn.H() will not be correct a
 
UEqn.H() will not be correct as you have currently formulated UEqn. You need to move the fvc::div term from the UEqn solve statement to the UEqn construction:

tmp<fvvectormatrix> UEqn
(
fvm::div(phi, U)
- fvm::Sp(fvc::div(phi),U)
- fvm::laplacian(2*mu+lambda, U)
- fvc::div
(
mu*gradU.T()+lambda*I*tr(gradU)-(mu+lambda)*gradU
)
);

UEqn().relax();

solve
(
UEqn() == - fvc::grad(pd) + fvc::grad(rho)*gh
);

liugx212 March 10, 2006 00:23

Hi friends, I also want to
 
Hi friends,

I also want to use the buoyantFoam case to simulate the sequestration. It means that I need add the Darcy term and source term in solver. But I am not sure what do I do. Could you please give some advice?

Thanks advance.
Guoxiang


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