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George May 13, 2005 07:59

pressure correction
 
Hi everybody. I have a quastion about my code.I simulate compressible unsteady turbulent flow and I want to ask you exactly how I implement the pressure correction (SIMPLE-like algorithm for compressible flow).What is the difference with the pressure correction in incompressible flow? Thank you!

ag May 13, 2005 08:37

Re: pressure correction
 
You will need to incorporate the variation of density with pressure in the continuity equation, i.e. the pressure correction you solve for will be a function of the velocity perturbations and density fluctuation. This is usually done by appealing to the thermodynamic relation rho = rho(p,h) and assuming the enthalpy is fixed during the outer iterations so that one can approximate drho/dt ~ (drho/dp)*dp/dt. In addition, the enthalpy equation is solved along with the momentum equations to give approximations to (u,v,h). Then the pressure correction equation is solved and the quantities are updated as appropriate. More on this can be found in Peric and Ferziger, pp. 278-287.

Larry Clark May 21, 2005 12:47

Re: pressure correction
 
In my program I found that upwinding the pressure and density using the Mach number helped greatly with the stability of the method. It added to the calculations but it is worth it. Otherwise I did just what the previous comment suggested.


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