Work: Sound radiation into liquid under cavitation. Moscow State University.

Main results: Elasticity of liquid under cavitation falls down and as consequence sound speed is decreased. At high cavitation indexes a speed of radiator approaches a sound speed and radiation process becomes substantially nonlinear. New physical phenomena are observed. This problem is of high priority due to development of the new ultrasonic processing. In a theory a nonlinear equation of plane piston vibration under the action of external harmonic force is analyzed. Riemann wave is supposed to be radiated. Numerical methods of integration are used. It is demonstrated that already in linear approximation at Mach numbers closed to unity profile of radiated wave is distorted and high order harmonics are appeared in a wave spectrum. Experimental investigation of the problem is prepared now. Magnetostrictive transducer excites vibrations at frequency 18 kHz. Titanium velocity transformers of special form are used to increase the intensity of vibrations. Electrical power of a driving generator is 5 kW that is allowed to create strong cavitation in water and other liquid. Intensity measurements of ultrasonic field are executed by acoustics gage and thermocouple probes. A system for automatic data collection and their farther processing is designed.