Supersonic Drag Reduction with Repetitive Laser Pulses Through a Blunt Body

The drag over a 20-mm-diam, Hat-nosed cylinder with repetitive laser pulse irradiations ahead of it was experimentally measured in a Mach-1 92, in draft wind tunnel Ten-ns laser pulses (wavelength, 1047 nm) were focused using a plane-convex lens fabricated on the nose of the cylinder at a repetition frequency of up to 10 kHz and power of 70 W at a maximum The steady state drag was measured using a low-friction piston, which was backed by a load cell in a cavity at a controlled pressure Within the limited laser performance, 3% drag decrease and efficiency of energy deposition of up to 10 were obtained on a time averaged basis The stronger the interactions between the laser-heated gas and the bow shock wave, the larger the amount of drag reduction became, however, with degraded performance of laser power transmission to the flow