Consideration of Self-Excited Aerodynamic Tone from Semi-Annular Cavity

Abstract

Controlling vortex flow fluctuation is one of basic technologies for improving the sound quality of aerodynamic noise. The timing of vortex shedding might be effective on the sound quality of self-excited aerodynamic tone. Some detail considerations with respect to an air flow around a semi-annular cavity were examined to make clear the timing of vortex shedding by only experimental datum with such air flow. The acoustic resonance in the cavity would be affect dominantly on the vortex shedding but the resonance mode would not directly decide the flow pattern in the cavity. The gradient of acoustic pressure fluctuation which induce some negative pressure region behind the vortex might be the dominant factor on the timing of vortex shedding from the upstream side edge of the cavity.