Multiphase VOF not converging
 

I am simulating a steady state stratified two phase 2D channel flow with periodic boundary conditions.

The residuals (all) oscillate for the default values of URFs. However, when I reduce the residuals of k, w & P to 0.1 the oscillations vanish and the solution converges (extremely slowly).

Is it advisable to do so?


P.S: I have changed grid sizes, ran unsteady state simulations. Nothing seems to prevent the oscillations when the URFs are at default values.