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Old   February 28, 2012, 08:47
Default Supercavitation problem
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emil
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Hi! I'm working on a supercavitating hydrofoil. I made a simulation of the cavitating flow around the hydrofoil (2 phases, flow, turbulence, vapor equation). The “velocity inlet” is set to 25m/s, vaporization pressure to 1700Pa, density od water is 999kg/m3, density of water vapour 0,015 kg/m3, viscosity of water 0,00114 kg/ms, visc. of water-wapor 9e-10 kg/ms.

My problem is that the Cl and Cd of the supercavitating hydrofoil are enormous (Cl=200000 and Cd=6000) they should be a little higher than the Cl and Cd found with just turbulence modelling (Cl=3.5 Cd=0.07).
Any ideas?

Thanks
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Old   February 28, 2012, 17:51
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Have you checked the reference values?
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Old   February 29, 2012, 13:32
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The reference values are the same for the 2 simulations.

Area, velocity are set to 1
density to 1.225 kg/m3
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Old   February 29, 2012, 18:26
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I'm not sure, but i think that area=chord length*hydrofoil depth,
velocity has to be set 25m/s and density has to be set 999kg/m3.

I' m looking forward for answers from other guys of the forum!!
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Old   March 3, 2012, 22:21
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Yes of course! silly me!!! The „Cl“s of the SCHFoil and the one without cavitation are of the same order of magnitude if multiplied by the appropriate density. (999 kg/m3 for water and 0.015 for water vapor),
thanks
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