VOF Convergence Problems for Accelerating Oil Pans

A Witry

Hello Everyone

I am modeling an oil pan with 2 fluids using VOF + GeoReconstruct + URelax=1 + Courant=0.25 + PISO + SkewCorrect with 1 iteration + Body Weighted DS + 1st order for everything. I have tried to reduce the time step and underrelaxation factors for fractions and pressure and momentum but I still find that my continuity diverges rapidly especially when the solution goes onto the next time step (first time period converged). The main fluid is set to be oil and the secondary one is air. I also tried reducing UR for k, e, momentum and Pressure without success.

The upper fluid is air and the fluid at the bottom is engine oil. By applying 3 acceleration components x, y, z, simulating the move of the vehicle around a curved road with radial and axial accelerations, the two fluids are set to "move" around the oil pan (which is just closed and has no inlets/outlets). The highest acceleration is 2.2g and the time step is now 0.00001 sec. I don't think that I can lower it any further!!!

Any ideas anyone? Anyone knows a majic setup that works??!! Thanks in advance.

Al