Entrainment and mixing in gravity currents: the role of gravity waves

Density currents, driven by the density contrast between two fluids, are an important class of geophysical flow, pertinent to atmospheric, terrestrial, deep marine and inner earth environments, yet their mechanics remain poorly understood. Critical to understanding density currents is the turbulent motion of the flow, dictating the distribution of flow density via turbulent diffusion and ambient fluid entrainment. This project will investigate entrainment, a poorly understood yet vital mechanism to understand how density currents maintain significant excess density whilst at the same time sustaining continuous entrainment. Experimental and numerical based research will address how such processes scale with flow size.

The majority of previous experimental studies acquired two-dimensional low-resolution data. This project will deliver a step-change in observational based understanding of flow dynamics, using revolutionary optical techniques to collect high-resolution planar, 3D flow velocity and concentration data. Complementing this will be the development of a numerical model to enable the study of turbulence scale

and interaction with entrainment in density currents, linking the laboratory to real-world flows. This project will provide a valuable insight into the controls of this important class of geophysical flow.