Problems with simpleFoam with flow in pipe
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Hi everyone!! I need a little help. I'm performing a 3D simulation of laminar, incompressible flow in a straight pipe. When analizing my results, i found them a little bit confusing. The thing is, that, instead of finding that the flow is parabolic, it develops into a parabolic-like profile but "translated" from the origin, that is, a parabolic manner but that in the walls is not zero. The detalis of the results can be seen in the attached images.
As boundary conditions for U, i set a parabolic profile with max_vel = 0.46 m/s at inlet, zeroGradient at outlet, and zero for the wall. For p, i set it to zero at the outlet. (see the o files for U and p attached) I also attach the fvSolution and fvSchemes files. In addition, i check the residuals, and they seem to converge nicely (see Ux residual plot attached) The tubes dimensions are diamater = 0.003 m and lenght = 0.01 m, the cinematic viscosity (nu) is 3e-6, and turbulence is off. Anyone may have an idea of what is happening? |
Extra-comment: I also performed the simulations with a surfaceNomalFixedValue for inlet velocity, and happens the same, the flows develope into this "shifted" parabolic profile.
Helpppp!!! jajajaja |
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Hi Fernando,
here is a case with surfaceNormalFixedValue as boundary condition and your specifications. My velocity profile looks ok... Run "blockMesh" first... Martin |
Thanks a lot!!! Apparently, although i was setting turbulence off, in RASmodel i was setting kepsilonmodel, instead of laminar.... :D. I think that would correct my results!
Graciassssssssss |
Quote:
I am entry level Open Foam User, When I saw in the system/fvSchemes and system/fvSolution files..I found k and epsilon equation are set to solve.. ================================================== divSchemes { default none; div(phi,U) Gauss upwind; div(phi,k) Gauss upwind; div(phi,epsilon) Gauss upwind; div(phi,R) Gauss upwind; div(R) Gauss linear; div(phi,nuTilda) Gauss upwind; div((nuEff*dev(grad(U).T()))) Gauss linear; } laplacianSchemes { default none; laplacian(nuEff,U) Gauss linear corrected; laplacian((1|A(U)),p) Gauss linear corrected; laplacian(DkEff,k) Gauss linear corrected; laplacian(DepsilonEff,epsilon) Gauss linear corrected; laplacian(DREff,R) Gauss linear corrected; laplacian(DnuTildaEff,nuTilda) Gauss linear corrected; } =========================================== Since the problem is laminar, why are you solving for k and e equation..? can you help me ??? |
Hi,
these settings are ignored if simulation is set to be laminar in constant/turbulenceProperties or constant/RASProperties. Martin |
Dear Martin,
Thank You for quick reply...:):) |
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