Transport of positively buoyant particles in wave run-up on a sloped, porous boundary

While the transport of sediment in waves of nearshore regions has long been of interest, little is known about positively buoyant particles in these systems. For example, coastlines have been observed to act as both a source and sink for microplastics in the ocean, but predicting how these particles are deposited and removed from beaches remains relatively unknown. These systems are highly complicated where the physical processes acting on these positively buoyant particles are influenced by particle size, beach properties, and hydrodynamics. A particular region of interest is the swash zone, where wave uprush and backwash occurs. Uprush and backwash are the upward and downward motions of shoaling waves on a sloped beach. In this poster, we study the transport of positively buoyant particles along a sloped, porous boundary. By generating water bores towards an artificial beach, we can create the upward and downward motion that would transport particles along the slope. In these idealized experiments, we control the size and shape of the particles, the size and speed of the water bore, and the porosity of the artificial beach. Our results illustrate the relative importance of waves, particles, and boundary parameters in this system.