Geophysical Fluid Dynamics: Stratified Flows

Gravity currents play a critical role in transporting momentum, heat, and mass in environmental and geophysical flows. While the behavior of single release gravity current has been studied extensively, the dynamics of colliding gravity currents within a stably stratified ambient remain poorly understood. This study presents a detailed numerical investigation of the dynamics and interactions that arise when two gravity currents propagate toward each other and collide in a stably stratified ambient. High-resolution large-eddy simulations were performed to capture the complex turbulence and interfacial instabilities that govern the flow evolution. Key parameters examined include the relative densities and release timing of the colliding currents, as well as the strength of ambient stratification. The analysis focuses on the collision height, the formation of instabilities such as Kelvin–Helmholtz billows, and the energy exchange between gravity currents composed of fluids with different densities under varying stratification.