Supersonic Drag Reduction with Repetitive Laser Pulses Through a Blunt Body

摘要

The drag over a 20-mm-diam, flat-nosed cylinder with repetitive laser pulse irradiations ahead of it wasnexperimentally measured in a Mach-1.92, in-draft wind tunnel. Ten-ns laser pulses (wavelength, 1047 nm) werenfocused using a plane-convex lens fabricated on the nose of the cylinder at a repetition frequency of up to 10 kHz andnpower of 70Wat amaximum.The steady-state dragwasmeasured using a low-friction piston,whichwas backed by anload cell in a cavity at a controlled pressure.Within the limited laser performance, 3%drag decrease and efficiency ofnenergy deposition of up to 10were obtained on a time-averaged basis.The stronger the interactions between the laser-nheated gas and the bow shock wave, the larger the amount of drag reduction became, however, with degradednperformance of laser power transmission to the flow.