Direct Shadow Method Application to Aero-Acoustic Interaction Investigation
Some investigation results for interaction process of saw-like sound waves of high intensity (160–170 dB) with axisymmetrical subsonic and supersonic jets are presented. Flow and sound waves visualization was performed by the direct shadowgraph method using an impulse source with exposure duration 2*10-7 s. Peculiarities of disturbance emergence and development in a subsonic air jet and in a helium jet under acoustic excitation are considered. It is shown that large-scale disturbances arise on the acoustically excited side of a supersonic jet and the jet radiates directional sound at the frequency of the external excitation (Mach waves).
KeywordsVortex Convection Helium Photography
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