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-   -   Solver selection of supersonic compressible flow (https://www.cfd-online.com/Forums/main/146067-solver-selection-supersonic-compressible-flow.html)

Leeoo December 17, 2014 21:13

Solver selection of supersonic compressible flow
 
Dear Friends:
This is my frist time posting a thread.
I am simulating the supersonic compressible flow and I have tried the Density-Based Solver(DBS) and Pressure Based Solver(PBS), but the simulation resaults via the two solver were very diiferent. I really did not know why and which solver was suitable. I've been confused for a long time and is very eager to get help.

tas38 December 17, 2014 22:45

Quote:

Originally Posted by Leeoo (Post 524440)
Dear Friends:
This is my frist time posting a thread.
I am simulating the supersonic compressible flow and I have tried the Density-Based Solver(DBS) and Pressure Based Solver(PBS), but the simulation resaults via the two solver were very diiferent. I really did not know why and which solver was suitable. I've been confused for a long time and is very eager to get help.

Pressure based solvers are generally more suited for only "mildly" compressible flows, say up to Mach 0.3. Beyond this value, density based solvers are typically preferred.

Leeoo December 17, 2014 23:03

Quote:

Originally Posted by tas38 (Post 524446)
Pressure based solvers are generally more suited for only "mildly" compressible flows, say up to Mach 0.3. Beyond this value, density based solvers are typically preferred.

Thank you for your advise. Another question:Are these two solvers will lead to different results?

tas38 December 18, 2014 21:42

I believe the main issue using pressure based for high Mach number flows and likewise using density based solvers for low Mach number flows has to do with efficiency rather than accuracy. Density based solvers become very stiff as the Mach number decreases as the incompressible limit is approached. However, there are some specialized compressible solvers which implement some pre-conditioning that do perform well for low Mach number flows.

Leeoo December 18, 2014 22:02

Thank you, your reply was helpful for me!


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