Off axis acoustic radiation force on cylindrical particle in plane traveling wave

Acoustic radiation forces on a cylindrical particle have been investigated in distinct kind wave fields such as stationary wave, plane traveling wave and Gaussian wave, etc. Prior computations of forces were carried out along the direction of acoustic wave propagation neglecting side direction force because of the symmetry of sound field. However, off-axis radiation force, which is significant in acoustic manipulation by artificial structure, is still unexplored. In this work, acoustic radiation force theory in side direction is delivered, and numerical calculations are presented for different direction angles and materials. It is concluded that off-axial radiation force is closely related to the incident angle. Negative radiation forces emerge at some angles. Therefore, we can change the incident angle through acoustic artificial structure to achieve better particle manipulation. The work will be useful in acoustic tweezers for the case of sound waves incident at any angle.