Anisotropic, implicit momentum source term

chris_j_meyer · June 11, 2013, 07:58

Hi All

Will not bore you with the details, but I am adding a momentum source term that is anisotropic. To do this explicitly is quite easy as a volVectorField with the sources can just be added to the U-equation. For an implicit formulation the following can be used and added to the U-equation:

fvm::Sp(a, U)

However, "a" can at best be a volScalarField and hence the source will be locally isotropic. Is there any way in which I can add different implicit source terms to the momentum equations in the three coordinate directions?

Chris

Lieven · June 11, 2013, 11:56

Hi Chris,

Have a look at the implementation of the porous media source term. I think this is what you are looking for.

Cheers,

Lieven

ski · July 18, 2013, 19:42

I'd like to do this too..

Issue is that it appears to be using Jacobi method to solve, which tends to give poor convergence rates. Anyone have any experience on this?

mateusps · July 25, 2016, 17:11

Hello y'all,

I have the same problem: how to program an anisotropic implicit source in the momentum equation?

fvm::Sp simply does not accept a tensor as coefficient (fvm::Sp(tensor,vector) does not seem to be implemented).

Did anyone find a way?

Thanks

June 11, 2013, 07:58	Anisotropic, implicit momentum source term	#1
chris_j_meyer New Member Chris Meyer Join Date: Mar 2009 Location: Cape Town, Western Province, South Africa Posts: 6 Rep Power: 17	Hi All Will not bore you with the details, but I am adding a momentum source term that is anisotropic. To do this explicitly is quite easy as a volVectorField with the sources can just be added to the U-equation. For an implicit formulation the following can be used and added to the U-equation: fvm::Sp(a, U) However, "a" can at best be a volScalarField and hence the source will be locally isotropic. Is there any way in which I can add different implicit source terms to the momentum equations in the three coordinate directions? Chris

July 25, 2016, 17:11	Did anyone find a way to program an implicit anisotropic source???	#4
mateusps New Member Mateus Palharini Schwalbert Join Date: May 2011 Posts: 22 Rep Power: 15	Hello y'all, I have the same problem: how to program an anisotropic implicit source in the momentum equation? fvm::Sp simply does not accept a tensor as coefficient (fvm::Sp(tensor,vector) does not seem to be implemented). Did anyone find a way? Thanks

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June 11, 2013, 11:56		#2
Lieven Senior Member Lieven Join Date: Dec 2011 Location: Leuven, Belgium Posts: 299 Rep Power: 22	Hi Chris, Have a look at the implementation of the porous media source term. I think this is what you are looking for. Cheers, Lieven

July 18, 2013, 19:42		#3
ski New Member AS Join Date: Jul 2009 Posts: 16 Rep Power: 17	I'd like to do this too.. Issue is that it appears to be using Jacobi method to solve, which tends to give poor convergence rates. Anyone have any experience on this?