[TommyM]

Hi All,
I have a question about compressible solvers.

Could anyone know if RhoPimpleFoam is considered as a pressure-based or a density-based solver?
Thank you in advance.

[Cyp]

It is a pressure-based solver because you solve an equation for the pressure. The solver is named rhoPimpleFoam because it handles compressible fluid and in this case the pressure equation depends on the time variation of the density (related to the time variation of the pressure using a compressibility factor).

Cheers,
Cyprien

[TommyM]

Ok. Thank you very much for your help.

[LuckyTran]

Pressure-based vs density-based are historical names and really shouldn't be used anymore. And really it only comes up when someone is coming from a Fluent background. If you are asking if rhoPimpleFoam behaves more like Fluent's pressure-based or more like Fluent's density-based solver then the answer is that it is closer to Fluent's pressure-based solver.

Originally Posted by Cyp

The solver is named rhoPimpleFoam because it handles compressible fluid and in this case the pressure equation depends on the time variation of the density (related to the time variation of the pressure using a compressibility factor).

You have to be careful accepting this as the explanation because actually this makes it precisely a density-based solver according to Fluent's explanation of what is pressure-based and density-based (using a rho equation and from there calculating pressure based it density-based).

You can get more precise answers by asking what is the exact technique used to solve the coupled set of pde's (continuity, momentum, energy, etc.). In Fluent, the pressure-based solver is a segregated solvers and density-based solver is a coupled solver.

[Didu]

Originally Posted by Cyp

It is a pressure-based solver because you solve an equation for the pressure. The solver is named rhoPimpleFoam because it handles compressible fluid and in this case the pressure equation depends on the time variation of the density (related to the time variation of the pressure using a compressibility factor).

Cheers,
Cyprien

Dear Cyp,

what do you mean with a compressibility factor? Bulk modulus, is it possible to adjust ?