Turbulence in breaking gravity waves - a computational study

Fluid flows in which the density varies ('stratified flows') are common in many important industrial contexts and in the atmosphere and oceans. The existence of turbulent patches generated by breaking waves is well known to operators of both aircraft and submersibles. What is much less clear is the character of the turbulence in such patches and the extent to which the source of the patches can be deduced from the nature of the turbulence. We propose studying the generation and characteristics of turbulence within breaking waves in a stratified flow using computational techniques (LES - Large Eddy Simulation). Previous studies have been restricted to very low Reynolds number - i.e. to flows of the kind that can be studied in the laboratory; this project will be one of the first attempts to use LES to study more practically relevant flows (i.e. flows at higher Reynolds numbers). This will entail substantial modifications to an existing numerical code, which will lead to production of a more widely applicable tool for LES studies of high Reynolds number, stratified turbulent flows. The code will than be used to study the characteristics of turbulent patches produced by the breakdown of large-scale gravity waves, typically generated by the influence of bottom topography on a stratified upstream flow, and thence to allow comparison of such turbulence with that generated via other mechanisms.