Abstract

Acoustic Nonlinearity, Attenuation and Scattering of a Sound in Water with Vapor-Gas Bubbles

V.A.Bulanov, I.V.Korskov (Institute of Marine Technology Problems, Far Eastern Branch Russian Academy of Sciences, Vladivostok, Russia)

e-mail: bulanov@marine.febras.ru

Nonlinear effects, attenuation and scattering of a sound, originated in propagating of a sound in a liquid with vapor-gas bubbles, are investigated. A liquid with phase inclusions near to phase transition represents an example of complex media, when at determination of the acoustic characteristics it should take into account phase transformations. It is shown theoretically, that nonlinear parameter, sound absorption and scattering coefficient are sharply changed at presence of phase transformations. This phenomenon is connected to occurrence of the additional mechanism of nonlinearity and sound energy dissipation, caused by phase transformations. The most significant increase of nonlinear parameter and attenuation factor occurs in case in liquid there are inclusions with the sizes, close to length of a thermal wave at frequency of a sound. Experimental researches of sound propagation in water with bubbles are conducted at temperatures from 18C up to 92C. Data on temperature dependence of acoustic nonlinearity of a water with vapor-gas bubbles are obtained, which show the meaning of influence of phase transformations at increase of the relative contents of water vapor in comparison with concentration of gas within the bubbles. The effects of attenuation of a sound on bubbles also show strong dependence on temperature.

Section : 4