271 Flow Visualization of a Resonant Sound Emission in Transonic Cavity flow with High Speed Video Camera

抄録

Flow around a two-dimensional cavity was investigated experimentally at Mach number from 0.55 to 085 at two different L/D ratios (1 and 2). To get the different L/D ratios the length of the cavity was varied (20 and 40mm) in keeping the depth constant (20mm). The schlieren technique was used to visualize the cavity flow. The images are captured by the high-speed video camera by which 40500 frames can be captured in 1 sec. The convection speed of the vortices in the shear layer was calculated from the captured images. It was found that the convection speed decreases with the increase of the L/D ratio. The flushmounted pressure transducer was used to measure the pressure fluctuation over he cavity. The amplified pressure data were analyzed by FFT. The pressure amplitude becomes larger with the increase of the length to depth ratio of the cavity.