Three-dimensional receptivity of hypersonic sharp and blunt cones to free-stream planar waves using hierarchical input-output analysis

Abstract

Hypersonic boundary layers are susceptible to flow instabilities that cause laminar flow to transition to turbulence, significantly increasing aerodynamic drag and wall heating. We focus on how these instabilities are triggered by the environment by applying a control systems theory technique called ``input-output analysis'' that relies in part upon solving the Navier-Stokes equations in reverse, tracing instabilities back to their origins. In the complex interactions between atmospheric disturbances, shock waves created near the nose cone of a hypersonic vehicle, and boundary layer instabilities, we find two physical processes strongly connected to the bluntness of the nose cone tip.