Three-dimensional ALE-FEM method for fluid flow in domains with moving boundaries part 1: algorithm description

Abstract

A three-dimensional finite element method for simulating fluid flow in domains containing moving objects or boundaries is developed. This method is a type of arbitrary-Lagrangian-Eulerian, based on a fixed mesh that is locally fitted at the moving interfaces and recovers its original shape once the moving interfaces go past the elements. The moving interfaces are defined by marker points so that the global mesh is not affected by the interfaces motion, eliminating potential for mesh entanglement. The result is an efficient and robust formulation for multi-physics simulations. The mesh never becomes unsuitable by continuous deformation, thus eliminating the need for repeated re-meshing. The interface boundaries are exactly imposed Dirichlet type. The total domain volume is always calculated exactly thus automatically satisfying the geometric conservation law. This work supports the internal combustion engines simulator KIVA developed at Los Alamos National Laboratories; in this paper, only the interface moving aspect is addressed.