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Convergence in multiphase flow !! HELP !!!

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Old   September 26, 2002, 04:47
Default Convergence in multiphase flow !! HELP !!!
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lohen
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Hi, i'm making gas-liquid flow simulations. I began with time step equal to 1e-06 s, otherwise convergence is impossible. it began then to converge, and i can fix time =1e-04s, but after a few time step, convergence is more and more difficult to reach and I have to lower the time step size. Can somebody explain me why ?????

Thanx
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Old   September 26, 2002, 10:10
Default Re: Convergence in multiphase flow !! HELP !!!
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Atholl
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Try increasing the time step by smaller increments!
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Old   September 27, 2002, 03:43
Default Re: Convergence in multiphase flow !! HELP !!!
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lohen
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yes I did that, but when I get from 1e-06 to 1e-05, it takes 10 to 5 iteration per time step to converge. So I get to 1e-04, then it convergences. And after a few time steps, convergence stops. And time step size wants to be lowered. Thanx though !!!
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Old   September 27, 2002, 16:27
Default Re: Convergence in multiphase flow !! HELP !!!
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Newbie
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try smaller underrelaxation parameters.

newbie
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Old   October 3, 2002, 11:28
Default Re: Convergence in multiphase flow !! HELP !!!
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Pravesh Kumar
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Hi you can use adaptive time stepping method in place of fixed.
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