An adaptive numerical scheme for solving incompressible 2-phase and free-surface flows

In this paper, we present a numerical scheme for solving 2-phase or free-surface flows. Here, the interface/free surface is modeled using the level-set formulation, and the underlying mesh is adapted at each iteration of the flow solver. This adaptation allows us to obtain a precise approximation for the interface/free-surface location. In addition, it enables us to solve the time-discretized fluid equation only in the fluid domain in the case of free-surface problems. Fluids here are considered incompressible. Therefore, their motion is described by the incompressible Navier-Stokes equation, which is temporally discretized using the method of characteristics and is solved at each time iteration by a first-order Lagrange-Galerkin method. The level-set function representing the interface/free surface satisfies an advection equation that is also solved using the method of characteristics. The algorithm is completed by some intermediate steps like the construction of a convenient initial level-set function (redistancing) as well as the construction of a convenient flow for the level-set advection equation. Numerical results are presented for both bifluid and free-surface problems.