EXPERIMENTAL INVESTIGATIONS OF RESONANT AERO-ACOUSTIC EXCITATION OF CAVITY DEPTH MODES BY A FLOW

摘要

Results of experimental parametric studies of resonance aero-acoustic excitation of cavity depth modes in flows with a low subsonic velocity (U ＜ 50 m/s) and transonic (0.7 ＜ M ≤ 1.045) velocity are generalized. Special attention is paid to the fundamental mechanisms responsible for this phenomenon. The conditions of appearance and interaction of these mechanisms are determined. The relationships between the parameters of flow and cavity are determined, upon which the maximum of aero-acoustic resonant excitation of depth modes takes place. These relationships take into account the difference between the flow velocity and the characteristic velocity of propagation of disturbances downstream. Experimental data showing the reliability of the relationships are presented. The range of the Strouhal number, in which the excitation of acoustic modes can be treated as aero-acoustic resonance, is determined.