Dimensionless variables
Hi everybody!
I wonder if it is possible to use dimensionless variables in OpenFOAM? I tried it on my own and it didn't work. For example, using icoFoam, we can transform continuity and momentum equations to form: div U = 0 D U/ Dt = 1/Re laplacian(U) - grad p and icoFoam produces fatal error and exits: Quote:
So the only solution seems to to be using same dimensions, but rescaling values. But it is not correct from formulation side... Is there any other solution? Waiting for your response! Have a good day! |
Already found some answers on forum at
http://www.cfd-online.com/Forums/ope...-mesh-etc.html and at http://openfoamwiki.net/index.php/Ma...al_checking.3F Answering possible future questions why I'm using dimensionless calculations - first, it is better numerically to use dimensionless variables, and second, than its is possible to compare two different flows, two different process regimes and so on. |
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Thank you, Bernhard!
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Hi,
can you please explain the dimensions of each term in icoFoam, fvVectorMatrix UEqn ( fvm::ddt(U) + fvm::div(phi, U) - fvm::laplacian(nu, U) ); solve(UEqn == -fvc::grad(p)); Actually, I am trying to solve NS by non-dimensionalizing, i edited code like this fvVectorMatrix UEqn ( fvm::ddt(U) + fvm::div(phi, U) - fvm::laplacian(1/Re, U) ); solve(UEqn == -fvc::grad(p)); There comes an error in laplacianSchemes, so edited form is like this: laplacianSchemes { default none; laplacian((Re^-1),U) Gauss linear orthogonal; laplacian((1|A(U)),p) Gauss linear orthogonal; } Can you please comment over my approach, along with dimensions of each term in solver file. I would really appreciate your help. Many Thanks Umar Quote:
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