Fig. 1. Schematic of positions of the interacting particles in the acoustic field.

Fig. 2. Comparison between numerical and analytical solutions of particle velocities due to acoustic entrainment: (a) d_p = 0.5 μm; (b) d_p = 5 μm.

Fig. 3. Comparison between numerical simulation results and experimental observations of particle interaction process (inset shows the particle trajectories during 6T before collision): (a) f = 5000 Hz; (b) f = 900 Hz.

Fig. 4. Influence of initial orientation angle on particle interaction: (a) Trend of particle interaction, inset shows particle trajectories at = 40°; (b) time required for the particles to achieve collision.

Fig. 5. Influence of initial particle position ( ) on particle interaction: (a) Trend of particle interaction, inset shows particle trajectories at = 0.375λ; (b) time required for the particles to achieve collision.

Fig. 6. Influence of particle diameter on particle interaction: (a) Trend of particle interaction, inset shows particle trajectories at diameters of 1 μm; (b) time required for the particles to achieve collision.