Turbulence and coherent structures in subsonic submerged jets. Control of the turbulence

The onset of turbulence and formation of large-scale patterns (coherent str uctures) in subsonic submerged jets are considered from the standpoint of n oise-induced nonequilibrium phase transitions of the second kind. It is sho wn by the example of noise-induced oscillations of a pendulum with a random ly vibrating suspension axis that such a transition can be controlled by an additional harmonic action. The known possibility of notable suppression o r intensification of turbulence in jets and free shear layers by means of a slight acoustic action at one or another frequency can be attributable to such control.