Solver selection of supersonic compressible flow

Leeoo · December 17, 2014, 21:13

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

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

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!

December 17, 2014, 21:13	Solver selection of supersonic compressible flow	#1
Leeoo New Member Leeoo Join Date: Dec 2014 Posts: 4 Rep Power: 11	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.

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December 18, 2014, 21:42		#4
tas38 Senior Member Troy Snyder Join Date: Jul 2009 Location: Akron, OH Posts: 219 Rep Power: 18	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.

December 18, 2014, 22:02		#5
Leeoo New Member Leeoo Join Date: Dec 2014 Posts: 4 Rep Power: 11	Thank you, your reply was helpful for me!