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- - **GammaEqn and UEqn in interFoam**
(*https://www.cfd-online.com/Forums/openfoam-solving/59749-gammaeqn-ueqn-interfoam.html*)

Dear all,
Could anyone explDear all,
Could anyone explain the following terms in interFoam solver? 1. In gammaEqn.H What does the third term on the l.h.s of gammaEqn mean? fvm::div (-fvc::flux(-phir, scalar(1) - gamma, gammarScheme), gamma, gammarScheme) Is it something like correction term to maintain mass conservation? From what is this term derived? 2. In UEqn.H What does the term (fvc::grad(U) & fvc::grad(muf)) on the l.h.s of UEqn account for? I've been browsing this forum for answers, but so far couldn't find any. Thank you, brian |

Without fussing about it too mWithout fussing about it too much:
- in the momentum equation, (fvc::grad(U) & fvc::grad(muf)) is a different formulation of the div(mu (grad U)^T) term, which does not go away when mu is non-constant - in the gamma equation the term (-fvc::flux(-phir, scalar(1) - gamma is an alternative form of the relative velocity term. This is what you get when you reformulate ddt(gamma) + div(gamma U_gamma) = 0 in the form that will use the volume velocity U instead of phase velocity gamma. For more details, I would recommend a good Thesis from dr. Henrik Rusche: @PhdThesis{Rusche:PhD, author = {Rusche, H.}, title = {Computational fluid dynamics of dispersed two-phase flows at high phase fractions}, school = {Imperial College, University of London}, year = 2003 } Hrv |

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