The plane jet, visualized by the smoke, with the parabolic mean velocity profile at the nozzle exit: without acoustical action (above) and with acoustical action (below)
a) without acoustical action
b) with acoustical action
In this movie, the plane jet is developed under conditions of the parabolic mean velocity profile formed directly at the nozzle exit. Therefore, the sinusoidal oscillation of the jet caused by its absolute instability can be observed. Under the acoustical effect on the jet with the same intensity of sound for frequencies from 30 to 90 Hz, some features of this acoustical effect can be observed.