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Difference between pEqn.flux and fvc::snGrad(p) |
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January 24, 2015, 23:17 |
Difference between pEqn.flux and fvc::snGrad(p)
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#1 |
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Ganesh Vijayakumar
Join Date: Jan 2010
Posts: 44
Rep Power: 16 |
If I had a pEqn defined as follows
fvScalarMatrix pEqn ( fvm::laplacian(p) ); Could some one tell me the difference between pEqn.flux() and fvc::snGrad(p) * mesh.magSf() Here are some of the other threads I've seen in this regard. http://www.cfd-online.com/Forums/ope...rix-faceh.html http://www.cfd-online.com/Forums/ope...ux-method.html I know about faceH, the simple/piso algorithm. However, if what I understand about them is right, there should be no difference between pEqn.flux() and fvc::snGrad(p) * mesh.magSf(). And yet there is. Why? Dr. Jasak says faceH is computed the way it is for consistency purposes. Could some one throw more light on this matter please. ganesh |
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January 19, 2022, 06:13 |
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#2 |
Senior Member
Dongyue Li
Join Date: Jun 2012
Location: Beijing, China
Posts: 838
Rep Power: 17 |
For this simple case, it equals exactly to
fvc::snGrad(p) * mesh.magSf() * fvc::interpolate(rAU) You just need to multiply 1/A. I think the reason is that eqn.flux() is more effective, since it only needs to use the information of lduMatrix. When implicit advection plays a role, it is more effective.
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