Novel Methodology for Viscous-Layer Meshing by the Boundary Element Method

Abstract

A configuration of prismatic elements in boundary layers created by marching a surface triangulation on viscous walls along certain directions is a typical mesh for viscous-flow simulations. The quality of the resulting elements and the reliability of the meshing procedure thus highly depend on the computing strategy used to determine the marching directions. In this study, the authors propose to compute a field of marching directions governed by Laplacian equations. This new approach can ensure the smooth transition of marching directions, and thereby lead to more desirable element shapes. In addition, the possible intersections of boundary-layer elements growing from the opposite sides of a narrow region can be identified by analyzing the vector field. With respect to the solution of the governing equation, the boundary element method is preferred because of its advantageous solution accuracy. Because the boundary element method only needs a surface-triangulation input, there is no need to create a volume background mesh. Following the aforementioned idea, a new hybrid prismatic meshing method is developed, and the capability of the method is demonstrated by meshing experiments on models with complex geometries.