Experiments on Mixing in Gravity Currents

We present new quantitative experimental data which elucidates the process and evolution of the mixing in gravity currents driven by aqueous salt solutions. We combine experiments in which we track parcels of dyed fluid, with carefully calibrated light attenuation experiments in which we measure the evolution of the salinity throughout the current. We thereby determine where mixing occurs and how it impacts the flow by drawing together experimental measurements of head concentration, current volume and Froude number as well as the lateral and vertical variations of salinity and depth throughout the current over time. Entrainment and dilution may be key in assessing the hazards of a dense gas release and in modelling the dynamics of particle laden flows.