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unphysical behaviour in buoyantSimpleFoam at inclined surfaces |
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March 12, 2013, 11:09 |
unphysical behaviour in buoyantSimpleFoam at inclined surfaces
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#1 |
Member
hannes
Join Date: Mar 2013
Posts: 47
Rep Power: 13 |
Hi there,
I wanted to run a case with the buoyantSimpleFoam solver but got some strange behaviour of the flow - at an inclined wall the hot air moves in the direction of gravity. For comparison I ran the same case with a vertical wall and got the expected result. Moreover, running the case with the inclined wall with the buoyantBoussinesqSimpleFoam solver also gives the expected results. - see attached images inclinedWall_Uz2.jpg straightWall_Uz.jpg inclinedWallBoussinesq_Uz2.jpg The boundary conditions were the following: p_rgh internalField uniform 101325; boundaryField { hotWall { type buoyantPressure; value $internalField; } fixedWalls { type buoyantPressure; value $internalField; } } U internalField uniform (0 0 0); boundaryField { hotWall { type fixedValue; value uniform (0 0 0); } fixedWalls { type fixedValue; value uniform (0 0 0); } } k internalField uniform 0.1; boundaryField { hotWall { type compressible::kqRWallFunction; value uniform 0.1; } fixedWalls { type compressible::kqRWallFunction; value uniform 0.1; } } epsilon internalField uniform 0.01; boundaryField { hotWall { type compressible::epsilonWallFunction; Cmu 0.09; kappa 0.41; E 9.8; value uniform 0.01; } fixedWalls { type compressible::epsilonWallFunction; Cmu 0.09; kappa 0.41; E 9.8; value uniform 0.01; } } mut internalField uniform 0.01; boundaryField { hotWall { type compressible::epsilonWallFunction; Cmu 0.09; kappa 0.41; E 9.8; value uniform 0.01; } fixedWalls { type compressible::epsilonWallFunction; Cmu 0.09; kappa 0.41; E 9.8; value uniform 0.01; } } Can anybody tell me whether this is a bug or my boundary conditions are not suitable? Thanks a lot, Hannes Last edited by hanness; March 12, 2013 at 11:19. Reason: error in bc for k |
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March 14, 2013, 05:52 |
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#2 |
New Member
Join Date: Aug 2012
Posts: 13
Rep Power: 13 |
Hi Hannes,
this looks really strange. Which schemes did you use? The fluid is an ideal gas? Bye RMF |
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March 14, 2013, 09:49 |
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#3 |
Member
hannes
Join Date: Mar 2013
Posts: 47
Rep Power: 13 |
Dear RMF,
yes, the fluid is calculated as ideal gas. The used schemes are as follows: ddtSchemes { default steadyState; } gradSchemes { default Gauss linear; } divSchemes { default none; div(phi,U) Gauss upwind; div(phi,h) Gauss upwind; div(phi,K) Gauss upwind; div(phi,k) Gauss upwind; div(phi,epsilon) Gauss upwind; div(phi,R) Gauss upwind; div(R) Gauss linear; div((muEff*dev2(T(grad(U))))) Gauss linear; } laplacianSchemes { default none; laplacian(muEff,U) Gauss linear uncorrected; laplacian((rho*(1|A(U))),p_rgh) Gauss linear uncorrected; laplacian(alphaEff,h) Gauss linear uncorrected; laplacian(DkEff,k) Gauss linear uncorrected; laplacian(DepsilonEff,epsilon) Gauss linear uncorrected; laplacian(DREff,R) Gauss linear uncorrected; } interpolationSchemes { default linear; } snGradSchemes { default corrected; } fluxRequired { default no; p_rgh; } anybody any idea? Thanks a lot Hannes |
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March 15, 2013, 09:17 |
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#4 |
Member
hannes
Join Date: Mar 2013
Posts: 47
Rep Power: 13 |
thanks to Henry I got the solution:
"Inclining the wall makes the mesh non-orthogonal but you choose an uncorrected laplacian but a corrected snGrad. If you correct for non-orthogonality the flow goes in the expected direction." |
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April 2, 2013, 06:11 |
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#5 |
Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 26 |
hi Hanness.do we use unCorrected in orthogonal meshes only and for non normal faces(non-orthogonal) use corrected?should both laplacian and snGradSchemes be the same?am i correct?when we use limit?
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