Adjoint-Based Adaptive Mesh Refinement for Sonic Boom Prediction

Abstract

Output-driven mesh adaptation is used in conjunction with an embedded-boundary Cartesian meshing scheme for sonic-boom simulations. The approach automatically refines the volume mesh in order to minimize discretization errors in pressure signals located several body-lengths away from the surface geometry. Techniques and strategies used to improve accuracy of the propagated signal while decreasing total number of cells are described. Investigations include examination of cell aspect ratio and comparisons with manual mesh adaptation. The effectiveness of this approach is demonstrated in three dimensions using axisymmetric bodies, a lifting wing-body configuration, and both the F-5E and Shaped Sonic Boom Demonstration flight-test aircraft. Results are validated with available experimental data for a variety of signal forms. These comparisons show that accurate pressure signatures can be produced for three-dimensional geometry in just over an hour using a conventional desktop PC.