An investigation of the mechanism of acoustic vibrations in swirl flows

An experimental setup is developed and systematic measurements are performed of pressure fields and amplitude-frequency characteristics of acoustic vibrations generated by impact swirl flows. A stable effect is revealed of generation of resonance acoustic vibrations under conditions of efflux of impact swirl jets. Curves are given of distribution of pressure on the obstacle surface for different values of the width of gap between the obstacle surface and the vortex chamber. The emergence of acoustic resonance with a frequency dependent on gas flow rate is registered for a certain correlation between the geometric parameters of the region of efflux of impact swirl air jet. An approximate analytical solution based on the use of a physical model of acoustic flow is obtained for theoretical description of the observed phenomenon of acoustic resonance in an impact swirl jet.