A model for the motion of particles driven by acoustic and hydrodynamic effects in the vicinity of a cylindrical collector has been previously reported. This trajectory model was developed to describe the essential physics that underlies an ultrasonically aided particle-filtration process in which a porous mesh is used to capture particles two orders of magnitude smaller than the pore size. To validate this trajectory model, experiments were performed to elucidate the detailed motion of particles in the neighborhood of a single cylindrical collector. Images of 54-μm-diameter polystyrene particles in aqueous suspension responding to acoustic and hydrodynamic forces were analyzed. Particle trajectories, calculated using only experimentally measured parameters as model inputs, well predicted the experimental observations. Adjustment of the local magnitude of the acoustic field, which accounts for spatial nonuniformities in the field, results in improvements in the correspondence between the trajectory predictions and the experimental observations.