Acoustic radiation pressure, torques, and scatterings: Insight for today from Gideon Maidanik's thesis research

Abstract

Renewed interest in the identification of structural contributions to the scattering by complicated objects and the radiation forces and torques on simple objects in complicated acoustic beams makes it timely to review aspects of Maidanik's thesis research [J. Acoust. Soc. Am. 29, 738-742 (1957); 29, 936-940 (1957); 30, 620-623 (1958)]. Maidanik and Westervelt recognized the importance of King's earlier study of the low-frequency radiation forces on rigid movable spheres and extended that work to ka of 10. Hickling and Wang (1966) examined the properties of the scattering by such spheres and more recently Marston [J. Acoust. Soc. Am. 125, 3539-3547 (2009)] found that such a sphere approximates the low ka backscattering by an aluminum sphere in water. It was also found that negative radiation forces were possible for movable rigid spheres in a helicoidal Bessel beam. Recently, subtraction of complex amplitudes for movable semi-rigid targets has been used to isolate elastic contributions in finite-element based computations for finite cylinders [D. B. Thiessen et al., J. Acoust. Soc. Am. 129, 2686 (2011)]. Maidanik's analysis of radiation torques has recently been reconciled with other approaches [L. K. Zhang and P. L. Marston, J. Acoust. Soc. Am. 129, 1679-1680 (2011)]. [Work supported by ONR and NASA.]