Characterizing Stratospheric Aerosol Particles and Particle Effects on Hypersonic Flight Vehicles

Abstract

Micro-particles in the form of aerosols are present at cruise altitudes of operating hypersonic vehicles. As these particles traverse the flow-field around a vehicle, they generate small-scale disturbances. These disturbances can interact with the boundary layer, potentially leading to laminar-turbulent transition and a substantial increase in surfaceheating. Even if the boundary layer is not receptive to particle-induced disturbances, the thermal protection system may still sustain damage from particles impacting the surface. A notable challenge to addressing these issues is that particle sizes and concentrations in the atmosphere are not well-characterized, particularly at the high altitudes where hypersonic flight vehicles operate. This lack of characterization partly prohibits an accurate assessment of the implications of aerosol particles on future hypersonic missions. The first part of this dissertation presents in-situ measurements of particle size distributions and concentrations in the lower stratosphere obtained through various weather balloon campaigns. The second part utilizes data from these campaigns in numerical simulations of hypersonic flows to investigate their influence on boundary layer transition and potential damage to the vehicle surface.