A HYBRID LEVEL-SET-CAHN-HILLIARD MODEL FOR TWO-PHASE FLOW

Martin Kronbichler
Division of Scientific Computing
Department of Information Technology
Uppsala University


Abstract:

We present a hybrid level-set-Cahn-Hilliard model for the simulation of two phase flow at small scales. Our method combines accurate contact line dynamics in the Cahn-Hilliard equation close to walls with the computationally cheaper level set method in interior regions where the full Cahn-Hilliard dynamics are not necessary to describe the flow. The combined model is coupled to the incompressible Navier-Stokes equations, where surface tension acts as a forcing term. The gains of the method are twofold: the equations to be solved in the interior are structurally easier than the Cahn-Hilliard equation and, more importantly, the level set model can accurately model two-phase flow already at coarser meshes. For oil expulsion by inflowing water we are able to obtain results of comparable quality when using less elements than with a Cahn-Hilliard model on the whole domain.