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Casey June 6, 2008 00:34

Free Surface Calculation
 
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.

murash-v June 7, 2008 04:59

Re: Free Surface Calculation
 
It must be transient. Example like you (1636KB): http://www3.msiu.ru/~murash-v/widsh.avi

post-treatment question June 7, 2008 06:05

Re: Free Surface Calculation
 
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?

murash-v June 7, 2008 06:28

Re: Free Surface Calculation
 
volume or mass? I have compressible gas

Casey June 8, 2008 00:47

Re: Free Surface Calculation
 
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.

Pauli June 8, 2008 10:17

Re: Free Surface Calculation
 
Grid refinement & time step.

Andrea June 8, 2008 12:21

Re: Free Surface Calculation
 
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

Casey June 13, 2008 18:59

Re: Free Surface Calculation
 
Thanks everyone.


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