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Old   June 17, 2009, 13:11
Default Problematic Mass Flow Case
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jpo
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Dear All,

I am unable to run a learning case due to convergence problems. Could you advise on the following:

The case is steady k-epsilon Standard, has one mass flow inlet and two pressure outlets, the fluid is air.
Mass flow inlet is set at 3kg/s
Outlet1 is set at target mass flow rate of 1kg/s
Outlet2 is set at 101 kPa.

The case crashes if courant number/URFs are at default, so I tried decreasing them. At Courant number = 0.1 it runs, but
residuals oscillate (for say 20,000 cycles) and stay high. Remeshing the model with finer mesh didn't help much. For this reason I am inclined to
think that my case setup is not the best.

I am free to vary the conditions at the two outlets, but don't know what parameters are reasonable and don't have
experimental data I could use, except that Outlet2 can be left open to the atmosphere and it can then be set to 101 kPa.
Appreciate your help.
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