Wave-Induced Particle Motions in the Ocean

Surface gravity waves at the surface of a fluid induce mass transport at the surface and in the fluid column below. Possibly the earliest result was given by Stokes who showed that periodic surface gravity waves induce a small forward drift: the Stokes drift, corresponding to the Lagrangian-mean wave-induced drift of an infinitesimally small tracer in the absence of Eulerian-mean flows. While Stokes's result is a clear-cut result on a second-order effect associated with linear waves, wave-induced particle motions in the ocean are far more complex in reality. Wave-induced particle motions can also arise because of Eulerian-mean flows driven by wave groups, in the (turbulent) surface boundary layer, subsurface flows, wave breaking, infragravity waves, the Earth's rotation, and the inertial dynamics of the particle itself.

This special issue will bring together researchers working on different aspects of wave-induced currents
and particle motions near the ocean surface, including theorists, experimentalists, and numerical analysts,
across different communities (oceanography, engineering, mathematics). Through a collection of reviews, brief reports, and full research articles, we aim to address recent developments in the study of wave-induced currents and particle motions in the ocean, and give perspectives for future research.

Fluid particle motions and wave-induced currents play an important role in air-sea interactions, sediment
erosion and transport, and in the distribution of marine litter pollution including microplastics. This special issue will focus on physical mechanisms by which surface waves in the ocean affect the motion of floating, suspended and submerged objects, including the motion of the fluid itself.