Three-dimensional acoustic radiation force of a sphere arbitrarily positioned in a Gaussian beam

Abstract

In this paper, a finite element model for calculating the acoustic radiation force of a rigid sphere in a Gaussian beam is setup to analyze the influence of the particle position on the axial and transverse acoustic radiation forces. The simulation results show that beam waist has effect on the values of the acoustic radiation force. When the beam waist is larger than the wavelength of sound waves, the changing law between the acoustic radiation force and ka will up to those of a plane wave. The effect of the particle position on acoustic radiation force is studied when the sphere arbitrarily lies in a Gaussian beam. For the condition ka=2π, the axial acoustic radiation force function is positive when the sphere lies near to the center of the beam and laterally within a certain distance from the beam center. As the particle gradually leaves the beam domain, the exerted axial acoustic radiation force will tend to zero. In addition, the exerted transverse force generally repels the particle away from the beam axis, except for the particle located on the waist plane and laterally within a certain distance from the beam center.