Hunter Boswell, a doctoral candidate in aerospace engineering, will defend their dissertation titled “Energetics and Impact Dynamics of Breaking Coastal Waves.” Their advisor, Dr. Frank D. Han is an associate professor in the mechanical and aerospace engineering department. Their co-advisor, Dr. Guirong Yan is an professor in the civil, architectural and environmental engineering department. The dissertation abstract is provided below.

This dissertation examines the detailed behavior of shallow-water waves as they shoal and break in the coastal environment. This is critical for properly designing civil structures and infrastructure in coastal regions, which face severe threats from hurricane induced flooding, wave impacts, and other coastal hazards. The use of numerical tools here is of key interest, due to the multi-scale nature of the wave breaking problem. In this study, we employ direct numerical simulations, which resolve all turbulent scales without modeling, to capture the dynamics of wave breaking at high fidelity and seek to capture the essential physics of the problem. We start by first considering the wave breaking event in isolation, where we study a solitary wave which shoals and breaks in a bathymetry analogous to a storm surge. We track the energy dissipation in the water phase and find that the dissipation rate collapses to a scaling predicted by established shallow-water theory. Further, we extend the problem to include wind forcing and study both the pre-breaking wind energy input as well as the wind effect on post-breaking waves. Next, we consider the solitary wave which impacts a wall in the same style of bathymetry and focus on how the different types of breaking waves affect the peak impacting pressure and find a key unifying trend across these morphologies. Finally, we consider the use of a multi-layer numerical model that approximates the vertical flow structure, in order to bridge the scale gap to more applied engineering problems and compare its performance to that of our direct numerical simulations.