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Old   September 15, 2011, 04:32
Question compressible+UDRGM+density-based=need advices
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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,
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Old   November 16, 2011, 18:59
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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.
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