SU2 Diverging at low subsonic mach numbers

averis007 · November 26, 2020, 07:06

I was using SU2 to run some simulations on the ONERA M6 wing. The standard transonic test case (M~=0.84) converged fairly quickly and produced results that were well in agreement with the validation results.
Problem occurred when I tried to simulate a low subsonic flow (M=0.25) over the same wing. SU2 won't converge no matter how low I set the CFL. I wanted to ask are there any known issues with SU2 at low mach numbers for 3D flows?

Few details regarding my simulation:
Solver = RANS, SA turbulence model
0.25 Mach, Compressible flow

aero_amit · November 28, 2020, 23:34

I would recommend you to try -

CONV_NUM_METHOD_FLOW= AUSMPLUSUP
or SLAU.

Switch off the multigrid if it is on -
MGLEVEL= 0

Also add -
USE_ACCURATE_FLUX_JACOBIANS= YES

You can try constant CFL initially (5, 10 or whatever works) and see if it goes through......

November 26, 2020, 07:06	SU2 Diverging at low subsonic mach numbers	#1
averis007 New Member Avijeet Join Date: Nov 2012 Posts: 18 Rep Power: 12	I was using SU2 to run some simulations on the ONERA M6 wing. The standard transonic test case (M~=0.84) converged fairly quickly and produced results that were well in agreement with the validation results. Problem occurred when I tried to simulate a low subsonic flow (M=0.25) over the same wing. SU2 won't converge no matter how low I set the CFL. I wanted to ask are there any known issues with SU2 at low mach numbers for 3D flows? Few details regarding my simulation: Solver = RANS, SA turbulence model 0.25 Mach, Compressible flow

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November 28, 2020, 23:34		#2
aero_amit Member Amit Join Date: May 2013 Posts: 85 Rep Power: 11	I would recommend you to try - CONV_NUM_METHOD_FLOW= AUSMPLUSUP or SLAU. Switch off the multigrid if it is on - MGLEVEL= 0 Also add - USE_ACCURATE_FLUX_JACOBIANS= YES You can try constant CFL initially (5, 10 or whatever works) and see if it goes through......