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Old   October 12, 2011, 09:38
Default Writing equations
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I have a question regarding how the Navier-Stokes is formulated in icoFoam.C file.

fvVectorMatrix UEqn
+ fvm::div(phi, U)
- fvm::laplacian(nu, U)

solve(UEqn == -fvc::grad(p));

Above, all density terms are simplified except the one included in phi (phi = rho x U). How is this possible?

Shouldn't it be something like below:

fvm::ddt(rho, U)
+ fvm::div(phi, U)
- fvm::laplacian(mu, U)
- fvc::grad(p)
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Old   October 12, 2011, 11:34
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David Gaden
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In icoFoam, since density is uniform and constant, it is pulled out of the equation. Even "phi" is actually volume flux.
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Last edited by marupio; October 12, 2011 at 11:34. Reason: Even "rho" is... changed to Even "phi" is
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