Acoustic radiation force on a free elastic sphere in a viscous fluid: Theory and experiments

An expression was derived from the theory for the acoustic radiation force (ARF) acting on a free spherical particle in a viscous fluid subject to an incident plane wave. In deriving this ARF, the viscosity of the fluid, the elasticity of the particle, and the particle's state when suspended freely in the liquid were considered together. Corresponding experiments were designed and conducted. To compare the ARFs measured in experiments with those predicted by theory, a sphere made of polystyrene was taken as the target particle. Based on experimental and theoretical calculations, the effects of the incident sound pressure amplitude, the frequency of the acoustic wave, and fluid viscosity were analyzed. The analysis showed that the ARF increases with increasing pressure amplitude or dynamic viscosity. There is a series of maxima or minima in the ARF that depends on dimensionless frequency kR. Moreover, the theoretical and experimental values are in good agreement. This work provides an advanced ARF theory that is able to predict real-world behavior more accurately.

Automated summary

An expression for the acoustic radiation force on a free spherical particle in a viscous fluid subjected to an incident plane wave was derived, considering fluid viscosity, particle elasticity, and the particle's state when suspended in the liquid. Experiments were designed and conducted to compare measured ARFs with theoretical predictions using polystyrene spheres. The analysis showed that ARF increases with pressure amplitude or dynamic viscosity, with maxima or minima depending on dimensionless frequency kR, and good agreement between theoretical and experimental values. This work provides an advanced ARF theory for more accurate real-world predictions.