The acoustic radiation pressure resulting from a plane wave incident on spherical shells and cylindrical shells immersed in a fluid is investigated theoretically in relation to the thickness of the shell and the contents of the hollow region. The results for the frequency dependence of acoustic radiation pressure computed on the basis of the theory are demonstrated for stainless shells with the hollow region filled water or air. Significant differences in acoustic radiation pressure occur when the interior region is changed from water to air.

This paper presents a new method for calculating the velocity potential q) of scattered ultrasonic waves from a rigid sphere placed in the field of waves emanating from a circular concave radiator in an infinite baffle. The solution q) is given in the form of an infinite series of spherical surface harmonics as a function of reduced quantities ka, krc, kb, kzo, etc., where k is the wave number, a is the radius of the circular concave vibrator, rc is the radius of curvature of it, b is the radius of the sphere, and Zo is the distance from the piston to the center of the sphere. The present theoretical framework has the advantages that it includes no numerical integrations and that it is applicable to elastic or compressible sphere cases with slight modifications of the boundary conditions.