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-   -   Cavitation (divergence) (https://www.cfd-online.com/Forums/fluent/32357-cavitation-divergence.html)

ROOZBEH October 21, 2003 04:13

Cavitation (divergence)
 
Hi; By the way I have to work with Fluent6.0.12 . Because your suggestion I increase velocity from 0 to 13m/s (2,4,6,8,10,10.5,11,11.5,12,12.5,13 m/s). But when cavitation occure, even with void fraction of .0001, the solution go to instability. I think this is caused by VOF equation at first. I have no way, only the relaxation number of .001 for vaporization mass and minimum of .1 for the others, remove this problem! I ran a case with this setting and got approximatly good results. But the time of cavity bubble development and dettachment is very high i.e. a low shedding frequency. Note that I do not use turbulence modification. I think my case has some problem: - low grid numbers near first cavity bubbles(I use 30000 mesh cell) - I have to modify the cavitation rate source term in the VOF eqwuation to model of "THREE-DIMENSIONAL UNSTEADY CAVITATION EFFECTS ON A SINGLE HYDROFOIL AND IN A RADIAL PUMP MEASUREMENTS AND NUMERICAL SIMULATIONS" By: "M. Frobenius, R. Schilling R. Bachert, B. Stoffel, G. Ludwig" I am trying to provide the new version of software. Thanks.


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