Acoustic Radiation Force on an Arbitrarily Placed Elastic Spherical Shell near an Impedance Boundary for Bessel Waves

A comprehensive formalism is presented for the acoustic radiation force acting on an elastic spherical shell near an impedance boundary in a Bessel wave field, where both the on- and off-axial configurations are considered. The general formula of the three-dimensional acoustic radiation force components is obtained based on the image theory and the translational addition theorem for spherical functions. Numerical examples are chosen for a water-filled polyethylene shell submerged in water, regarded as an ideal fluid without acoustic absorption. It is shown that increasing the reflecting coefficient of boundary enhances the magnitude of radiation force but does not influence the resonance frequencies. The spherical shell can be attracted towards the wave axis under selected conditions. A first-order Bessel wave is not circularly symmetrical and thus it does not exert a central force. An increase of the relative thickness leads to the shift of the radiation force peaks and dips as well as the decrease in their amplitudes. The results in this study can improve our understanding of the acoustic radiation force behaviors for spherical particles in a bounded field, especially in the off-axial configuration cases.