Enhancement of the Robustness on Advancing Layer Method with Trimmed Hexahedral Volume Mesh for the Generation of the Boundary Layer Grids

Abstract

When performing simulations using computational fluid dynamics, the grid systems in the viscous boundary layer regions are important because the velocity and pressure change very rapidly in these regions. Especially for the turbulent flows, thin grids should be arranged densely in the direction perpendicular to the wall. In this study, the advancing layer method, which has been applied mostly to tetrahedral meshes, is applied to trimmed hexahedral meshes. To generate boundary layer meshes with non-intersecting grid lines near the wall boundaries having concave corners and narrow gaps, the directional vectors of grid lines and faces are smoothed, and the displacement vector fields calculated using the Laplace equation were utilized. Firstly, the details on the newly developed methods are introduced showing simple two-dimensional cases as examples. After applying the methods for a complex three-dimensional geometry to check its applicability and investigating the generated grid systems, the numerical simulations of propeller open water test for INSEAN E779A marine propeller were carried out by simpleFoam, one of the standard solvers of OpenFOAM. The computational results showed good agreement with the experimental results. Therefore, in conclusion, the developed advancing layer method is an appropriate method for generating boundary layer grids of a trimmed hexahedral mesh.