Radiation Pressure and Acoustic Levitation

Abstract

The first half of the chapter develops the underlying theory for acoustic radiation pressure. Time-averaging the momentum equation leads to a compact general expression for radiation pressure in terms of the kinetic and potential energy densities. Distinctions between Eulerian, Lagrangian, Rayleigh, and Langevin radiation pressures are discussed. Solutions are derived for plane waves incident on perfectly reflecting and absorbing walls, and for sound beams incident on partially reflecting interfaces. The second half of the chapter is devoted to acoustic levitation, with derivations of acoustic radiation force on rigid and compressible spheres, and on gas bubbles in liquids.