Vendredi 27 juin 2025 à 11h00, salle des séminaires IRPHE
Abstract: Water waves travelling shoreward undergo dramatic transformations that shape coastlines. The flow dynamics are dramatically altered when waves break due to decreasing water depth and again when they collapse at the point when they reach the shore where the water depth is zero. In this talk, we consider these processes and the subsequent flow that is driven up the beach. We present theory and measurements of breaking waves approaching beaches at normal incidence and at oblique incidence angles. We present measurements of this flow in large-scale experiments with a focus on understanding the flow evolution in space and time, the effects of friction with the beach surface, and its potential to transport large amounts of sediment. We demonstrate the link between wave-driven flow on a beach and canonical solutions to the shallow water equations, which allows us to describe the flow using reduced-parameter models. Finally, we discuss extensions of this work that have applications to understanding transport of solutes and sediment on beaches.
Bio: Dr. Nimish Pujara was an undergraduate at Cambridge University and obtained his doctorate at Cornell University. After a postdoctoral position at UC Berkeley, he joined the Department of Civil and Environmental Engineering at University of Wisconsin – Madison as a faculty member. He now leads a group that pursues research in fluid mechanics with the aim of improving understanding of various environmental processes.