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Cavitation convergence problem

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Old   September 29, 2009, 11:41
Default Cavitation convergence problem
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Felipe Gutiérrez Donoso
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i´m studying cavitation in a knife valve preceded by 3 plate-horifice devices. The geometry is 2D. I´ve done a steady, turbulent (k-epsilon) simulation to stablish a initial flow field without activating the cavitation model. After have a good convergence I´ve included the cavitation model, changing the pressure-velocity coupling to Simplec and linear pressure discretization.

I´ve been testing many under relaxation factors but I have divergence with every of them. I´ve tried unsteady solution with 0.0001s time step, but obtained the same result.

Any advice on this??

Thanks in advance
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Old   September 30, 2009, 02:21
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Maxime Perelli
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Is your time step really adapted?
try to set dt as follow:
dt= 0.5 * (min cell size)/(max velocity expected)
For info, I set dt=1e-7..1e-6 for hydraulic devices
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Old   September 30, 2009, 15:46
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I´ve reduced time step, it´s iterating now... I´ll let you know the results. Thanks
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