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Effect of High-Repetition Rate Laser Energy Deposition on the Wave Drag of a Blunt Body in Hypersonic Flow
J. Fang, Y-J. Hong, Q. Li and H. Huang

The wave drag reduction on a hypersonic vehicle by laser energy depositions is studied herein. Using laser energy to reduce wave drag can improve vehicle performance. A second order accurate scheme based on the finite volume method and domain decomposition of the structural grid was used to compute the drag performance of cylinders in a hypersonic flow of Mach 6.5 at an altitude of 30 km with high-repetition rate energy depositions. The effects of Mach number on drag reduction were also studied. The results showed that the bow shock was changed into oblique shock from the interaction between the laser-induced blast wave and the bow shock over the blunt body. Also, the front-surface pressure was decreased. When the distance between the energy deposition location and the vehicle head was equal to the vehicle radius, the wave drag was reduced to 28.7% of the basic drag (without laser beam interaction), and the power effectiveness was 13.5 at Mach 6.5. The basic drag increased with increasing Mach number. At Mach 10 the power effectiveness was as high as 41.6, but the normalized drag was relatively low. Unfortunately the surface temperature of blunt body was increased due to the laser beam interaction.

Keywords: Wave drag reduction, laser, energy deposition, hypersonic flow, normalized drag, power effectiveness, high repetition rate, Mach number

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