Abstract: Coastal flows, particularly in estuaries, are characterised by intense turbulent kinetic energy dissipation and mixing, profoundly influencing their circulation, salinity structure, chemistry and biology, and thereby society. The complex dynamics of density-stratified turbulence span a vast range of eddies, from the forcing scale of 1-100 metres down to the micrometre scale at which molecular diffusion irreversibly mix the active scalar (typically salinity) and other passive scalars such as pollutants, nutrients and dissolved gases. Grasping the interplay between these small and large scales, and parameterising unresolved physics in regional and operational models pose significant challenges in the environmental fluid dynamics community. In this talk, I will demonstrate how new data-rich laboratory experiments can tackle these challenges. Firstly, I will show how an exchange flow in a tilted duct can sustain realistic turbulence in parameter regimes that are both environmentally relevant and computationally challenging. Secondly, I will explain how three-dimensional measurements of the velocity and density field enable us to explore small-scale physics with unprecedented precision and detail. I will present some key results and highlight avenues for future work and environmental applications.
Short Bio: Dr Lefauve is a research fellow in the G. K. Batchelor Fluid Dynamics Laboratory located in the Department of Applied Mathematics and Theoretical Physics (DAMTP) at the University of Cambridge.