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FSI simulation: flow against a membrane
Posted Feb 20, 2012, 9:22 a.m. EST 1 Reply
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I have simulation to run, where there is a perfusion of a fluid (say water) on an impermeable structure (say bladder patch) that cover all the diameter of a pipe, constrained to the pipe itself. In my simulation (attached) I apply a step function in order to gently increase the initial value of water speed, and I place the outlet beyond the bladder patch (since the deformed bladder is supposed to move the fluid after it) . The mesh is a fine free triangular (seems to me enough accurate), and I apply a time-dependent study in order to see how the bladder patch gets deformed (I expect a cupola shape). I don't want a stationary study since I guess the steady state in this situation is reached when the bladder patch gets broken.
It seems to me that all boundary condition are good, but still when I compute the study it says "Attempt to evaluate real square root of negative number". I guess that the fact that the water can not flow freely in the pipe because the bladder patch blocks it makes the solver crazy, but I can not find where the mistake is...
any hint?
Thanks for your kindness and for your attention
Best regards
Alberto
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Hello Alberto Urban
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I wonder if replacing inlet velocity condition to pressure condition would be ok. When I changed inlet boundary, boundary number 2, to ‘pressure, no viscous stress’ with ‘100*step1(t)’, I can get a cupola shape.
Regards,