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- - **A question about UEqn.H (interPhaseChangeFoam)**
(*https://www.cfd-online.com/Forums/openfoam/106332-question-about-ueqn-h-interphasechangefoam.html*)

A question about UEqn.H (interPhaseChangeFoam)the UEqn.H at interPhaseChangeFoam
fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(rhoPhi, U) - fvm::Sp(fvc::ddt(rho) + fvc::div(rhoPhi), U) - fvm::laplacian(muEff, U) - (fvc::grad(U) & fvc::grad(muEff)) //- fvc::div(muEff*(fvc::interpolate(dev2(fvc::grad(U) )) & mesh.Sf())) ); but the UEqn.H at interFoam fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(rhoPhi, U) - fvm::laplacian(muEff, U) - (fvc::grad(U) & fvc::grad(muEff)) //- fvc::div(muEff*(fvc::interpolate(dev(fvc::grad(U)) ) & mesh.Sf())) ); I don't understand why need - fvm::Sp(fvc::ddt(rho) + fvc::div(rhoPhi), U) at interPhaseChangeFoam , Could anybody please answer me ? thanks very much. |

fvm::Sp(fvc::ddt(rho) + fvc::div(rhoPhi), U)
this term would be zero mathematically because fvc::ddt(rho) + fvc::div(rhoPhi) is global continuity equation, and i guess it is added to consider any numerical error in global continuity equation |

I am agree with Nimasam. It returns the continuity equation value. I have checked the results in two conditions with and without this term. Results are fairly the same. However, I should say that by using this term it seems that the convergence speed is much better.
PS: in the OF22, this term has been removed! |

Quote:
Hi, have you been able to use interPhaseChange in OF21 or 22? I can get results by previous versions (i.e. OF1.5). But by these new versions results are not good at all. ABE |

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