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Heat transfer in a channel: solving for T; questions about Pe and solving |
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July 11, 2013, 09:27 |
Heat transfer in a channel: solving for T; questions about Pe and solving
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#1 |
Member
Join Date: Jan 2011
Posts: 45
Rep Power: 15 |
Hi,
I'm doing CFD for a wavy channel, using simpleFoam and the k-omega-SST model to solve the velocity field. I'd now like to solve for T, and did some intermediate processing (post-U, pre-T): For my first attempt at solving T (scalarTransportFoam) I used Code:
div(phi,T) Gauss upwind; Code:
// characteristic length of each cell: cbrt(V) volScalarField CLen ( IOobject ( "CLen", runTime.timeName(), mesh, IOobject::NO_READ, IOobject::AUTO_WRITE ), mesh, dimensionedScalar( "CLen", dimLength, 0. ) ); forAll (CLen, i) { CLen.internalField()[i] = Foam::cbrt(mesh.V()[i]); } // Pe number volScalarField Pe ( IOobject ( "Pe", runTime.timeName(), mesh, IOobject::NO_READ, IOobject::AUTO_WRITE ), mesh, dimensionedScalar( "Pe", dimless, 0. ) ); Pe = CLen*mag(U)/(alpha + turbulence->nut()/Prt); My main question now is: what can I do to get a usable temperature field? While Pe > 2 does not necessarily mean that the solution will be wrong, I could increase alpha and nu (in order to maintain Pr = 7), but that would mean that I have to increase U or the domain size as well to adjust Re. Wouldn't that just lead to the same problem, but on a different scale? Another possibility is of course that my code for Pe is just plain wrong. Maybe someone could comment on this; OF's Pe tool just calculates Pe at the boundary, using a different equation. I can not refine the mesh by a factor of 150, as I already have about 2 million cells. Regards |
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July 22, 2013, 06:01 |
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#2 |
Member
Artem Shaklein
Join Date: Feb 2010
Location: Russia, Izhevsk
Posts: 43
Rep Power: 16 |
Hello, buffi.
Try to use "limitedLinear 1" for convective fluxes. It will use linear and switch to upwind in areas with big variable value gradients. |
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