Feasibility Study of the Determination of Shock Detachment Distance and Ablation on Luminous Bodies Using a Laser Light Source

摘要

A laser light source was employed in a shadowgraph system in a 1000-foot hyperballistics range to investigate new techniques for observing the shock shape, detachment distance, and nose shape for luminous and ablating models at hypersonic speeds. Film fogging and distortion, usually present when the aerodynamic heating at high velocities causes ablation and luminosity at the nose of the model, were markedly reduced, using a selective focusing technique and a Q-switched ruby laser light source. Shock detachment distances measured directly from film plates compare well with the results from previous indirect techniques that are not applicable to luminous or ablating bodies. The method described shows promise for application to the study of model recession under simulated re-entry conditions and for investigation of the relation of model shape changes to ablation, shock shape, and shock detachment distance. (Author)