SOUND EMISSION BY A SYSTEM OF VORTEX RINGS

The emission of sound by a system of thin axisymmetrical vortex rings in an ideal infinite fluid is considered. Vortices generate the larges t sound field at the moment when one ring passes through another, that is, at the largest mutual influence of the rings. For this moment, th e sound pressure in the far field is estimated. The radiation efficien cy of a system of rings in an infinite medium is proportional to M(5), however, the coefficient of M(5) is defined by the type of interactio n of vortices and varies in a wide range (0.2-1000). The main regulari ties typical of the interaction of two coaxial vortices also manifest themselves in the case of the interaction of a system consisting of a large number of rings.