Decoupled Time Stepping Methods for Fluid-Fluid Interaction

A model of two incompressible Newtonian fluids coupled across a common interface is studied. The nonlinearity of the coupling condition exacerbates the problem of decoupling the fluid calculations in each subdomain, a natural parallelization strategy employed in current climate models. A specialized partitioned time stepping method is studied which decouples the discrete fluid equations without sacrificing stability and maintaining convergence. This is accomplished through explicit updating of the size of the jump in tangential velocities across the fluid-fluid interface by a geometric averaging of this data over the previous two time levels. A full numerical analysis is presented and computational tests are performed demonstrating the robustness of this method.