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-   -   Pressure vs. Density based (http://www.cfd-online.com/Forums/fluent/44553-pressure-vs-density-based.html)

jan April 29, 2007 12:12

Pressure vs. Density based
 
Dear all, I am calculating a compressible flow, a straight nozzle with high pressure at inlet. I am a mass flow inlet. What confuses me is that I get different results when using the pressure or density (coupled) based solver. All the settings are the same except selection of the solver. With the pressure solver I predict a Mach number on 1.4 at the inlet and with the density based is the Mach number 0.9. Hence velocity and pressures at the inlet face is also different.

Both solvers should give the same results if the solution is converged and it is.

Any clue/help

Regards Jan


Ahmet May 2, 2007 16:12

Re: Pressure vs. Density based
 
Hi,

I study also in a laval nozzle with high pressure inlet and also I have the same question. Did you have any answer for your problem.


John May 3, 2007 04:45

Re: Pressure vs. Density based
 
I did not get an answer on CFD online, but I have been told that it has to do with the interpolation scheme for the 2 solvers. A finere grid is required for the pressure based solver and if difference is seen in the results then it is probably due to a too coarse grid, no mesh independancy



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