Dynamical motion of a pair of microparticles at the acoustic pressure nodal plane under the combined effect of axial primary radiation and interparticle forces

The dynamical motion of a pair microparticles exposed to acoustic standing waves and located at the pressure nodal plane is studied using numerical simulations experiments. insight into their behavior along due competition between axial primary radiation interparticle forces elucidated. An expression for force acting on particle derived, dynamics simulated fluid-structure interaction model based arbitrary Lagrangian-Eulerian method. Considering total sum force, three distinct regimes are observed depending upon relative magnitudes which in turn depend gradient energy density. Acceleration, deceleration, constant velocity approaching particles observed, explained by interplay non-acoustic forces. predicted very good agreement with experimental observations.