Entrainment in stratified environments — an interface-based approach

In this study, we focus on understanding stratification effects on the entrainment process in gravity currents via a multi-scale approach based on the turbulent/non-turbulent interface (TNTI). We find that a large part of the reduction of the entrainment parameter in the presence of a stable stratification can be explained through a reduction of the surface area of the TNTI. An analysis of the fractal geometry of the TNTI reveals that the decrease of the surface area with increasing stable stratification is predominantly due to a reduced effective fractal dimension.