On wave-driven "shingle" beach dynamics in a table-top Hele-Shaw cell

The primary evolution of beaches by wave action takes place during storms. Beach evolution by non-linear breakingwaves is 3D, multi-scale, and involves particle-wave interactions. We will show how a novel, three-phase extension to the classic laboratory experiment is designed to create beach morphologies with breaking waves in a quasi-2D setting. Idealized beaches emerge in tens of minutes due to several types of breaking waves, with about 1s periods. The thin Hele-Shaw cell simplifies the inherent complexity of three-phase dynamics by reducing the turbulence. Given the interest in the Hele-Shaw table-top demonstrations at ICCE2014, we will also discuss how different versions of the Hele-Shaw cell have been constructed. Construction can be inexpensive thus yielding an accessible and flexible coastal engineering demonstration as well as research tool. Beach evolution is sufficiently fast and can start very far from equilibrium, allowing an unusually large dynamical range to be investigated.