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The results of experimental investigations on the effect of the transverse acoustic fluctuations for subsonic round jet formed in curved channel (d = 20; 9; 1.5 mm) are presented. Using laser – smoke visualization the jet instant picture sections were received, which showed the presence of two modes jets instabilities – Kelvin – Helmholtz vortices and Dean vortices and their interaction. The influence of the acoustic excitation frequencies on the jets are shown, in particular on a wavelength of Kelvin – Helmholtz instability. The picture of the diffusion combustion of propane jet with a nozzle diameter of d = 1,5 mm without acoustic excitation and with acoustic excitation are compared. It has been observed that the diffusion flame combustion of propane is subject to transformation by the action of the acoustic field and developing instabilities in the jet.

Results of the experimental studies of the subsonic round and plane both the macro and micro-jets are reported. The new phenomenon associated with transformation of the round micro-jets into the plane micro-jets under effect of a transversal acoustic field is revealed. It is shown, that its downstream development is determined by the sinusoidal instability mechanism of the plane jet. The disintegration phenomenon of the micro-jets on two jets developing separately from each other is revealed. It is found, that two new micro-jets are spreaded under a definite angle to each other and subjected by high-frequency secondary instability. It is shown, that sinusoidal instability of a plane jet is saved for macro and microjets both with acoustic and without acoustic effect. It is found, that the pseudo plane micro-jet at the presence of an acoustic field demonstrates presence in it of the vortex structures and dependence of the jet splitting angle from the frequency acoustic. The new phenomenon, so-called twist of a plane of a micro-jet on its edges in direction of the stream velocity vector created by a transversal acoustic field is revealed. It is shown, that process of the micro-jet twist result in a stupor of the jet downstream development and delay of its turbulisation. It is found, that sinusoidal instability of the round microjet depends on a direction of the acoustic field vector while the plane micro-jet does not depend. It is shown, that the new phenomena detected during investigations of a development both the round and plane micro-jet are stipulated by commensurability of the transversal acoustic field energy with the micro-jets energy.