[Mashiro5]

Dear All,

I'm experiencing significative differences in using interPhaseChangeFoam in OpenFOAM 4.1 with respect to results I had with the same solver in OpenFOAM 2.3.1

My test case is the well known NACA66 hydrofoil by Shen and Dimotakis (Shen YT and Dimotakis PE. The influence of surface cavitation on hydrodynamic force. In: Proceedings of the 22nd ATTC, St. Johns, NL, Canada, 8–11 August 1989, pp.44–53.).

I already simulated this hydrofoil using OpenFOAM 2.3 with quite satisfactory results, well in agreement with measurements. Attention was focused on averaged cavity length and hydrofoil performance with the presence of the cavity bubble rather than on re-entrant jets, bubble shedding at bubble closure and so on: 2D calculations with wall functions and the realizable k-epsilon turbulence model.

When I moved to OpenFOAM 4.1, I re-ran some old calculations to check if everything behaves similarly.
Unfortunately this is not the case. As you can see from the figures below, using OF 4.1 leads to significantly longer cavity bubbles (longer than OF 2.3 and in turn, to the experiments).
Calculations have been carried with exactly the same setup: same mesh, same numerical schemes (except for the new conventions in fvSchemes of OF 4), same numerics (exactly the same fvSolution file). Calculations were initialized with the same non-cavitating calculations in order to provide a realistic estimation of the pressure around the hydrofoil and avoid/limit the initial transient.

Do you have any explanation circa these differences?
Many thanks,
Stefano

[huangxianbei]

Maybe you should check the source code of the cavitation model. I'm still using Of-2.3.0 as it's boring to adapt my program to the new version.

[Mashiro5]

Of course, but I was looking for someone here in the forum who already had this problem. I do not think to have enough experience to deeply explore all the classes involved in an OpenFOAM solver except for a rough line-by-line comparison... :-)