Influence of Upstream Pulsed Energy Addition on Shock-Wave Structure in Supersonic Flow

A small-scale wind tunnel experiment has been performed to investigate the dynamics of the offbody energy addition upstream of an oblique shock wave generated by a wedge model. Off-body energy was simulated by laser-induced breakdown upstream the model in a Mach 2.4 flow. Laser pulses with the energy of about 350 mJ/pulse and with a pulse width of 10 ns were used to deposit the energy in the region of interest. The dynamics of the interaction were captured in both the schlieren and shadowgraphs images taken at 500,000 frames per second rates. In order to understand the complicated dynamics of the interaction between the thermal spot and its associated shockwave with the oblique shockwave from the model, computational calculations were performed. A two-dimensional, time-accurate Euler code was applied for this purpose. Good agreement between the theoretical and experimental results has been found. As expected, the laser-induced thermal spot indeed weakened the oblique shock. The images also show the dynamics of the interaction between shockwaves generated by the laser breakdown in the flow and the oblique shock, including reflections off the wedge body. The results from this near-field experiment can be used to optimize the energy addition for the practical applications including sonic boom reduction. 2002 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Influence of Upstream Pulsed Energy Addition on Shock-Wave Structure in Supersonic Flow Conference Paper