Author(s): Francesca De Serio, Michele Mossa
Linked Author(s): Francesca De Serio, Michele Mossa
Keywords: Plunging breaker; Coherent events; Turbulent fluctuations;
Abstract: Near-shore dynamics and costal sediment transport are strongly affected by turbulence induced by breaking waves in the surf zone. The present study examines the occurrence and spreading of turbulent vortex structures due to wave breaking and named coherent structures, primarily controlling sediment movements and possible tracers’ diffusion. Considering that previous studies have mainly focused on spilling waves in analogy with bores and jumps, in this experimental research we especially address to plunging waves, which are characterized by higher turbulence due to the presence of the overturning jet and the splash-up cycle. Measurements have been carried out by means of a Laser Doppler Anemometer in a wave flume, in the breaking region. Coherent motions are identified as a function of the wave phase and the bursting processes are quantified especially using the quadrant analysis technique. Useful hints to turbulence spreading and transport are obtained.