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-   -   Why rho coeffs are zero in compressible solvers? (http://www.cfd-online.com/Forums/openfoam-solving/110292-why-rho-coeffs-zero-compressible-solvers.html)

immortality December 7, 2012 06:18

Why rho coeffs are zero in compressible solvers?
 
in any comressibe solver like rhoCentralFoam and rhoPimpleFoam i have run
The rho residual coeffs are zero.why it is so?
And is it possible to see rho field in results without need for making changes in solver?

piccinini December 9, 2012 08:58

Hello, it is probably because density is being computed explicitly, using past time step values for phi field.

immortality December 10, 2012 03:49

thank you dear piccinini.but how about rhoCentralFoam?why rho,rhoE,rhoUx,etc coefficients are zero?in this solver rho Fields are calculeted from continuity because it is a density based solver.

piccinini December 10, 2012 20:04

yes, that's right. continuity equation is being solved, but in an explicit manner.

e.g.
Code:

        solve
        (
            fvm::ddt(rhoE)
          + fvc::div(phiEp)
          - fvc::div(sigmaDotU)
        );


immortality December 11, 2012 04:04

thanks dear piccinini.but could you explain more about explicit solution of rho?zero coeffs how are composed?and then how can i plot rho field in paraview or other plotters?

immortality December 14, 2012 13:09

thank you piccinini.but whats the difference between a density based and a pressure based solver?both calculate rho from other previous fields?and then why the zeros are showing from start to end?could you tell me what have openfoam providers been intended of this displaying manner?


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