Acoustic radiation force and motion of a free cylinder in a viscous fluid with a boundary defined by a plane wave incident at an arbitrary angle

The acoustic radiation force (ARF) is derived for a free cylinder immersed in a viscous fluid with a boundary defined by a plane wave incident at an arbitrary angle. Trajectories of a free rigid cylinder under the action of ARF are also investigated. Various aspects affecting the ARFs and trajectories of a free rigid cylinder, such as fluid viscosity, the incident angle of the plane wave, the density ratio of the fluid to particle, the particle radius, and boundary, are addressed in numerical simulations. Results show that ARFs are positive or negative depending on the various factors considered in this work. Moreover, the amplitude of the total ARF on a free cylinder in a bounded viscous fluid defined by a plane wave incident at a certain angle may decrease with increasing viscosity, which is significantly different from the case of a fixed cylinder immersed in a boundless viscous fluid. Furthermore, the trajectory of the particle changing with different conditions is investigated. We can predict and regulate the particle trajectory by selecting relevant parameters. The finite element method is implemented to validate the theoretical results. The finite element results and theoretical results are in good agreement. This work helps better understand the underlying mechanism of the particle manipulation using ARF.