CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   FLUENT (https://www.cfd-online.com/Forums/fluent/)
-   -   Supercavitation problem (https://www.cfd-online.com/Forums/fluent/97913-supercavitation-problem.html)

 emteh February 28, 2012 08:47

Supercavitation problem

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

 spk February 28, 2012 17:51

Have you checked the reference values?

 emteh February 29, 2012 13:32

The reference values are the same for the 2 simulations.

Area, velocity are set to 1
density to 1.225 kg/m3

 spk February 29, 2012 18:26

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!! :)

 emteh March 3, 2012 22:21

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