Strand-Grid-Solution Procedures for Sharp Corners

Abstract

The strand/Cartesian-grid approach provides many advantages for complex moving-body-flow simulations, including fully automatic volume grid generation, highly scalable domain connectivity, and high-order accuracy. In this work, the authors evaluate methods of handling sharp corners with strand grids through combinations of strand vector smoothing, multiple strands emanating from a single surface node, and telescoping Cartesian refinement into corner regions of the near-body grid. A new discretization strategy is introduced to better tolerate mesh skewness induced by strand smoothing. These approaches are tested for unsteady, laminar, and high-Reynolds-number turbulent flows. For standard viscous high-aspect-ratio grids, smoothed strands with telescoping Cartesian refinement provide the most accurate results with the least complexity. Mesh discontinuities associated with the use of multiple strands at sharp corners produce more error than with smoothed strands. With both strand approaches—vector smoothing and multiple strands—targeted Cartesian refinement is critical to capture features near sharp corners that strand grids alone are too coarse to capture.