compressible+UDRGM+density-based=need advices

PierreFz · September 15, 2011, 04:32

Hie everybody,
I model a plasma jet (hot temperature , 13000 K) issuing in air at atmospheric pressure with high velocity and temperature gradient. Multi-species model with an UDRGM is used in order to take into account the compressibility and to calculate the gas mixture properties by means of mixing laws and temperature dependant data. With an UDRGM, the density-based solver (that used the multigrid strategy) must be used. Is there anybody experienced with this kind of calculation that can help to set up the solver parameters? Indeed, the calculation failed by divergence even for low courant numbers.
Thanks a lot in advance for advices/help,

Pierre

ndabir · November 16, 2011, 17:59

I haven't done similar problem on plasma yet, but I have experience in high temperature and high pressure( 10 GPa) modeling.

try to use density base explicit solver and use AUSM for flux vector. also remember to set double precision when you are running your simulation. the latter will probably solve your convergence problem. you can also choose a smaller courant number at the begining of simulation and after the residuals get smoothed, use higher courant number to increase the speed of convegence.

September 15, 2011, 04:32	compressible+UDRGM+density-based=need advices	#1
PierreFz New Member PierreFz Join Date: Mar 2011 Location: France Posts: 1 Rep Power: 0	Hie everybody, I model a plasma jet (hot temperature , 13000 K) issuing in air at atmospheric pressure with high velocity and temperature gradient. Multi-species model with an UDRGM is used in order to take into account the compressibility and to calculate the gas mixture properties by means of mixing laws and temperature dependant data. With an UDRGM, the density-based solver (that used the multigrid strategy) must be used. Is there anybody experienced with this kind of calculation that can help to set up the solver parameters? Indeed, the calculation failed by divergence even for low courant numbers. Thanks a lot in advance for advices/help, Pierre

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
The Density of Compressible Flow	panou	Main CFD Forum	0	April 27, 2011 04:58
Problems with the density at walls for a compressible flow	david39	OpenFOAM Running, Solving & CFD	0	February 8, 2010 12:33
REAL GAS UDF	brian	FLUENT	6	September 11, 2006 08:23
Specified Operating Density for Compressible VOF	Andrew Wick	FLUENT	1	November 14, 2005 04:58
Warning 097-	AB	Siemens	6	November 15, 2004 04:41

November 16, 2011, 17:59		#2
ndabir Senior Member navid Join Date: Jan 2010 Posts: 110 Rep Power: 16	I haven't done similar problem on plasma yet, but I have experience in high temperature and high pressure( 10 GPa) modeling. try to use density base explicit solver and use AUSM for flux vector. also remember to set double precision when you are running your simulation. the latter will probably solve your convergence problem. you can also choose a smaller courant number at the begining of simulation and after the residuals get smoothed, use higher courant number to increase the speed of convegence.