Experimental Investigation on the Circular Cylindrical Cavity Noise at the Locked-on State

In the locked-on state, the ratio of resonant frequency to the fundamental frequency of self-sustained oscillation is suggested to play a key role in predicting the dominant tonal noise for the square cavity. In this paper, we similarly investigate the mechanism of coupled self-excited oscillation and acoustic resonance aerodynamic noise in cylindrical cavities with different depths at low speeds. The experimental noise field results are described for a circular cavity with a diameter of 78 mm and a depth ranging from 70 mm to 120 mm at an incoming flow velocity of 5 to 35 m/s. A strong self-excited oscillatory discrete noise is generated in this cylindrical cavity flow at the locked-on state and the parameter Rd is also well proofed to evaluate and predict the dominant mode order and the total sound pressure level peak.