Can someone explain briefly wh
Can someone explain briefly what this entry is used for?
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Yup, easy. Thin of the calcul
Yup, easy. Thin of the calculation of the fluxes in the pressure equation. Once everything is done properly, the pressure part of the flux is equal to the off-diagonal matrix coefficient related to the face, multiplied by the pressure field (difference, or for compressible flow, a slightly more complex).
Now, think of discretisation of a Laplacian: this one also got the non-orthogonal correction, which is explicit. The correction therefore also appears in the flux and must be fully consistent: if not, you get a mass continuity error. The best way to accumulate all corrections of this kind is to simply collect the stuff during matrix assembly. Because this costs money (storage and operations), you don't want to do this for every matrix assembly. Thus, a fluxRequired flag means "collect the explicit contributions", after which you can ask the matrix for the flux (or flux correction). If you don't need the flux, you don't do fluxRequired and all is well! Clear? Hrv |
Currently I am trying to use turbDyMFoam, but I get the following error:
Code:
BiCGStab: Solving for Ux, Initial residual = 1, Final residual = 8.72088e-14, No Iterations 1 Code:
fluxRequired Regards, Andy Edit: I found this thread: http://www.cfd-online.com/Forums/ope...ictionary.html and checked my fvSchemes. However, the problem was not fixed for me. |
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1) go to Santiago Marquez PhD Thesis here: https://docs.google.com/file/d/0B2lp...VLb3lGekk/edit 2) go to page 95 (MULES + PISO Algorithm explanation) You will see that in order to solve the flux at point 1.C, you need the to create a flux from 1.B. (fluxRequired: alpha.water). In the same manner, in order to solve the flux at point 3.D, you need first the flux of the gradient of the pressure calculated from 3.C (fluxRequired: p_rgh). So in this case we have to set: fluxRequired { default no; p_rgh; alpha.water; } in order to storage the flux created from the discretization of alpha equation in the MULES algorithm and the flux created from the pressure equation in PISO loop. This is what I understood from openFoam user guide |
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