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natrask August 13, 2010 14:45

Static vs dynamic pressure in Reynolds stress source term
My understanding of the divDevRhoReff function in the turbulence models is that it returns the deviatoric part of the Reynolds stresses, and that when the pressure equation is solved in the following part of the loop the contribution of the 2/3*rho*k term is lumped into the pressure in the momentum equation. Therefore, to get the static pressure, it's necessary to substract off the contribution of the turbulence.

However, when you look at the equations of state that are being used in many of the solvers, they are using the incorrect pressure (p = pstatic + 2/3*rho*k) to calculate the density. For strictly single phase flows, the difference is negligible, but for turbulent flows involving mixtures of liquid and gas this can make a significant difference in the resulting pressure.

Has anyone else given some thought to this situation? It seems that the majority of solvers in OpenFOAM use the same assumption, and I want to make sure that I'm not missing something.


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