LOCAL MESH ADAPTATION TECHNIQUE FOR FRONT TRACKING PROBLEMS

A numerical model is developed for the simulation of moving interfaces in viscous incompressible flows. The model is based on the finite ele ment method with a pseudo-concentration technique to track the front. Since a Eulerian approach is chosen, the interface is advected by the flow through a fixed mesh. Therefore, material discontinuity across th e interface cannot be described accurately. To remedy this problem, th e model has been supplemented with a local mesh adaptation technique. This latter consists in updating the mesh at each time step to the int erface position, such that element boundaries lie along the front. It has been implemented for unstructured triangular finite element meshes . The outcome of this technique is that it allows an accurate treatmen t of material discontinuity across the interface and, if necessary, a modelling of interface phenomena such as surface tension by using spec ific boundary elements. For illustration, two examples are computed an d presented in this paper: the broken dam problem and the Rayleigh-Tay lor instability. Good agreement has been obtained in the comparison of the numerical results with theory or available experimental data. (C) 1998 John Wiley & Sons, Ltd.