The Meshfree Finite Element Method for Fluids with Large Deformations

Abstract

The shallow water equations (SWE) is often simulated by using Eulerian descriptions. These phenomena may give rise to strong gradients and lead to large distortion of grids meshes. Hence classical finite elements methods may fall in simulating such problems. In this paper we present a meshless method, based on the natural element nethod (NEM). In a geometrical domain of a cloud of nodes, NEM uses the Voronoi cells and then its dual, namely Delaunay triangulation. Its main advantage lies in shape function of the natural neighbour interpolation, such that the position of natural neighbours is enough to its construction. To avoid the nonlinear term, the time material derivative term is discretized by a Lagrangian procedure. We also used an appropriate nodal integration technique to estimate integrals related to the diffusion, pressure and Coriolis terms because NEM shape functions are not polynomials and they are rational. For the diffusion term, the method of stabilized conforming nodal integration (SCNI) is proposed while for pressure and Coriolis terms a geometrical method will transform the integration over the cells domain to the integration over the edges. The method was successfully used to simulate dam-break flows by solving the fully 2D shallow water equations (SWE) by using an implicit scheme under a transient flow.