Harmonic radiation from a liquid-filled spherical acoustic lens with an internal eccentric spherical source

Radiation of sound from a modally vibrating shell-encapsulated (eccentric) spherical source is analyzed in an exact manner using the classical method of separation of variables. The proposed model is a realistic idealization of a spherical acoustic lens with focal point inside the lens when used as a sound projector. The analytical results are illustrated with a numerical example in which the modal acoustic radiation impedance load on the source and the radiated far-field pressure are evaluated for representative values of the parameters characterizing the system. Numerical results clearly illustrate that in addition to frequency, surface velocity distribution and eccentricity of the source, the dynamic interaction of the encapsulating shell can be of great consequence in sound radiation.