Automatic monitoring of element shape quality in 2-D and 3-D computational mesh dynamics

Abstract

One of the major problems in fluid–structure interaction using the arbitrary Lagrangian Eulerian approach lies in the area of dynamic mesh generation. For accurate fluid-dynamic computations, meshes must be generated at each time step. The fluid mesh must be regenerated in the deformed fluid domain in order to account for the displacements of the elastic body computed by the structural dynamics solver. In the elasticity-based computational dynamic mesh procedure, the fluid mesh is modeled as a pseudo-elastic solid the deformation of which is based on the displacement boundary conditions, resulting from the solution of the computational structural dynamics problem. This approach has a distinct advantage over other mesh-movement algorithms in that it is a very general, physically based approach that can be applied to both structured and unstructured meshes. The major drawback of the linear elastostatic solver is that it does not guarantee the absence of severe element distortion. This paper describes a novel mesh-movement procedure for mesh quality control of 2-D and 3-D dynamic meshes based on solving a pseudo-nonlinear elastostatic problem. An inexpensive distortion measure for different types of elements is introduced and used for controlling the element shape quality. The mesh-movement procedure is illustrated with several examples (large-displacement and free-boundary problems) that highlight its advantages in terms of performance, mesh quality, and robustness. It is believed that the resulting scheme will result in a more economical simulation of the motion of complex geometry, 3-D elastic bodies immersed in temporally and spatially evolving flows.