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Old   June 6, 2008, 00:34
Default Free Surface Calculation
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Casey
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In my simulation, I have gas being injected tangentially into a cylinder full of water and I want to observe the free surface after steady state is reached. I've used the "Free Surface" option in Pro-am, but the calculation either stops due to divergence or the end result doesn't look what I expect for steady state. Any suggestions on which settings to change to improve the Free Surface function? Thanks in advance.
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Old   June 7, 2008, 04:59
Default Re: Free Surface Calculation
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murash-v
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It must be transient. Example like you (1636KB): http://www3.msiu.ru/~murash-v/widsh.avi
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Old   June 7, 2008, 06:05
Default Re: Free Surface Calculation
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post-treatment question
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Is the initial volume of gas conserved in this example?

It does not seem to be. This happens in comet as well, there is a loss.

Have you done a graph plot total mass of gas versus time?
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Old   June 7, 2008, 06:28
Default Re: Free Surface Calculation
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murash-v
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volume or mass? I have compressible gas
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Old   June 8, 2008, 00:47
Default Re: Free Surface Calculation
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Casey
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The volume of gas isn't conserved. I realized that I made a mistake in my original description. The cylinder is not completely full of water, but mostly (maybe 80%). There is an outlet that the two phase mixture can leave through.
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Old   June 8, 2008, 10:17
Default Re: Free Surface Calculation
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Pauli
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Grid refinement & time step.
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Old   June 8, 2008, 12:21
Default Re: Free Surface Calculation
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Andrea
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try also to use an UD scheme for the sim...you can restart later with a MARS scheme if you want to be correct with the results... And try also to initialize the sim via initfi.f, not by auto-initialization...if you can do that you'd probably get a more "stable" simulation
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Old   June 13, 2008, 18:59
Default Re: Free Surface Calculation
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Casey
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Thanks everyone.
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