Characterizing mixing in a slope density current

Started: February 2016
Supervisor: Hughes, G.

Description of Research

Turbulent buoyancy-driven flows arise commonly in both the natural and the built environments, and most previous studies have focused on cases where these flows are aligned with either the vertical or horizontal directions. However, buoyancy-driven flows are often confined by sloping boundaries, and the dynamics governing these flows against horizontal and sloping boundaries – density currents – differ as soon as the slope forms an angle with the horizontal of order a degree or more. Turbulence is typically energized along the current interface, leading to entrainment and mixing with the ambient fluid. Previous studies have attempted to characterize entrainment in a slope density current, but a consistent and robust understanding and parameterization of this behaviour is yet to emerge.

In this study, we adopt a new approach to characterize mixing in slope density currents.

Figure 1
Buoyancy (m.s^{-2}) in an (x, z) plane, for a density slope current running down a slope of angle 10\degree with the horizontal, extracted from DNS data.

Background

Emily is a graduate with an MSc in Fluid Dynamics and Energetics from Paris-Saclay University, France.

Emily Dieu

Emily DieuFluid Mechanics Research Student 
Department of Civil & Environmental Engineering 

Imperial College London SW7 2AZ 
e.dieu16@imperial.ac.uk