Drag Reduction Performance due to Repetitive Laser Pulses on the Blunt Body

Supersonic wave drag reduction due to the repetitive laser induced energy deposition is performed experimentally in this study. Laser pulses are irradiated through a convex lens installed in side of the in-draft wind tunnel of Mach 1.94. The maximum frequency and power of the energy deposition is limited up to 50kHz and 400W. In order to estimate the drag reduction, time-averaged drag force is measured by a force balance system and stagnation pressure history is synchronized with corresponding sequential schlieren images captured by high-speed camera. Drag reduction performance is linearly increased up to 21% with input laser power. The power gain which only depends on the pulse energy, is realized by approximately 7. Virtual spike formation induced by highrepetitive energy depositions is remarkably discussed in the visualization results.