Abstract: We report on a measurement campaign conducted at a beach on the island of Sylt, located off the German North Sea Coast with the goal of understanding particle dynamics in the surf zone. Using oranges as particle tracers in connection with a dual two-camera stereo imaging system, we were able to track individual tracers as they cycle through the waves approaching the beach. It was found that the infragravity-wave signal has a major effect on the nature of the particle trajectories.

Using a Boussinesq model it is then shown that infragravity waves – even of very small amplitude – can induce large horizontal movements of particles. The simulation results hold across a number of situations including monochromatic waves, sea states and both with and without bathymetric forcing.

Short Bio: Henrik is a Professor of Applied Mathematics and Fluid Mechanics at the University of Bergen, where he is also the Associate Head of Department. His research focuses on mathematical modelling of physical systems, and in particular on the study of wave problems in fluids. His interests include wave breaking, particle drift and waves propagating through the ice-covered ocean, with practical applications that include the design of wave energy devices, prospects of tidal energy, carbon storage, and safety of ice roads.