Fig. 6.
(Colour online) a 3D streaming-induced drag forces on a particle with a radius of 30 µm (, N); b in-plane ; c out-of-plane [red arrow in (a)]; and d comparisons of maximum out-of-plane [peak in (c)] with the buoyancy forces for various particle sizes (radius of ). The inset in (c) shows the directions of the plotted forces above a vibrating antinode. and are the buoyancy and gravity, respectively