Simulation of Sharp Leading Edge Aerothermodynamics

Future hypersonic vehicles are likely to use sharp leading edges on wings and engine inlets to reduce drag. The radius of curvature associated with such structures may be one centimeter or less. The very small size leads to high heating rates that can be accommodated using advanced materials. An additional aspect of the small size concerns the basic gas dynamics. At such small scales, the continuum approach invoked in formulating the Navier-Stokes equations may be invalid. In this study, the flow around various sharp leading edge shapes is computed for a high-altitude point on a typical re-entry trajectory. The particle-based direct simulation Monte Carlo method (DSMC) is employed. Effects are investigated of variation in free stream velocity and leading edge shape in terms of flow field and surface properties. The aerothermodynamic performance of the sharp leading edges is assessed using the shock standoff distance, the total drag, and the heat transfer rate. The data generated in the present study form the initial part of a more complete investigation involving the optimization of leading edges over a hypersonic re-entry trajectory.