Experiment on buzz characteristics of two-dimensional, twin-duct supersonic inlet

An experimental investigation on the buzz characteristics of a two-dimensional，twin-duct supersonic inlet was carried out at Mach number 2.6. By analyzing the pressure variation law at different positions of the inlet， the flow characteristics were attained while the inlet operation changed from unstarting to restarting. Results showed two modes of buzzing at different throttle choking ratios: both of the inlet ducts buzzed together; one of the inlet ducts buzzed while the other one worked at a highly supercritical operation. By comparing the inlet pressure characteristics under different buzzing modes，it was noted that low-frequency oscillation was observed when both of the inlet ducts buzzed together，and the pressure variation was closely related to periodic shock wave movement. The buzz frequency was 21.5 Hz，and the peak value of the fluctuating pressure was about 75% of the total pressure of free-stream flow. On the contrary，high-frequency oscillating was noted when only one inlet duct buzzed，and the pressure oscillation was dominated by flow separation. The buzz frequency reached over 325 Hz，which was about 15 times of the frequency for the first mode of buzzing，and the amplitude peak was found to be approximate to the total pressure of free-stream flow. © 2024 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.