OpenFOAM v.2.x Courant Number 4 time higher then in previous versions
Hi Foamers!
I got and issue using OpenFOAM v2.x: Courant Number jumps 4 times if compare to OpenFOAM v1.6 and 1.7.x. I tried cases for different geometries ofcouse with the same setting between OF versions and result is always the same! Actually this issue results in a calculation time increasing 4 times. Unappropriated! Please, comment on that issue, what is your experience with v2.x usage? Cheer, Alex |
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Issue closed (http://www.openfoam.com/mantisbt/view.php?id=424#c1039):
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Will do more checks and report regarding actual calculation time. |
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Hi Alberto!
pimpleFoam. According to my test to keep the same Co number (with which solution does not diverge) actual calculation time increased 2 times (I remind with the same constant dt I've got Co_new_OF = 4*Co_old_OF). |
Slow down, to my opinion, is not 4 times because now turbulence is solved at last PIMPLE iteration. But of course I tried with turbulence updated each iteration: the same result, solution diverges with the dt I used before with old OF versions..
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Do you use any particular boundary condition? For example mapped, or time-varying, or custom BC? Some of these were updated in 2.x. |
Nope, standard k-epsilon (also tried with realizable which I mostly use) with standard wall functions for k, epsilon, nut, fixed values for U at inlet and zero gradient at outlet, pressure 0 at outlet and zero gradient at the inlet. I think it would be better if I upload here some test case. Will do it on Monday.
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Yes, that's a good idea. The BC's are surely not the reason.
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