Particle trajectories and terminal velocities in vertically oscillating fluids

The trajectories and terminal velocities of particles in vertically oscillating fluids have been studied by obtaining analytic and numerical solutions to the nonlinear Langevin equation representing a superposition of forces arising from particle acceleration, displaced fluid acceleration, buoyancy and particle‐fluid drag as represented by an nth‐power drag law. In vibrating fluids the directional particle velocities are found to be lower than in stationary fluids for drag exponents n > 1 and correspondingly higher for 0 < n < 1. The engineering significance of the results is discussed in relation to hold‐up, separation and transport phenomena in vertically oscillating multiparticle‐fluid systems.