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June 26, 2009, 04:52 |
simulation whitout a U equation
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#1 |
Member
Sven Degner
Join Date: Mar 2009
Location: Zürich
Posts: 55
Rep Power: 17 |
hi,
i write my own DES model and try next to simulate the correlation of the isotropic turbulence. But in this case I got some problems with the initial conditions. At the moment I got the velocity conditions, the problem is how it is possible to write the other fields for my fixed velocity field , in my case p,k,epsilon? the simple idea, solve the case without U equation till convergence and i got the matching field for my velocity field? original oodles something like this : fvVectorMatrix UEqn //the velocity equation ( fvm::ddt(U) + fvm::div(phi, U) + sgsModel->divDevBeff(U) ); if (momentumPredictor) { solve(UEqn == -fvc::grad(p)); } // --- PISO loop for (int corr=0; corr<nCorr; corr++) { volScalarField rUA = 1.0/UEqn.A(); U = rUA*UEqn.H(); phi = (fvc::interpolate(U) & mesh.Sf()) + fvc::ddtPhiCorr(rUA, U, phi); .......................... My question now how can edit the solver to solve my problem target: p , k , epsilon for my over the time fixed velocity field? best regard Sven |
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August 20, 2009, 06:48 |
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#2 |
Member
Markus Weinmann
Join Date: Mar 2009
Location: Stuttgart, Germany
Posts: 77
Rep Power: 17 |
Hi Sven
have you solved your problem already? In order not to solve for U, you could try to increase the tolerance on U such that U is never updated in the iteration process. I am also interesseted in how you have generated isotropic turbulence in OF? The reason why I am asking is because I want to calibrate a hybrid RANS/LES method using isotropic turbulence. Unfortunately, I was not very successful in generating isotropic turbulence until now. Do you have any tips? Markus |
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