Investigation of Interfacial Behavior in Density Current Collisions

This study provides a comprehensive examination of colliding density currents with a range of density differences from 1% to 4%, using controlled laboratory experiments with saltwater and freshwater. The research reveals that when density currents collide, they generate internal bore, with the denser fluid flowing consistently beneath the lighter fluid. A significant finding is the temporary stalling and oscillatory motion of the current fronts during collisions, which is linked to a partial dissipation of kinetic energy and the subsequent formation of internal waves. Numerical simulations showed close agreement with experimental observations, reproducing the location of the tidal fronts well and verifying the accuracy of the hydrodynamic model used. Moreover, the study demonstrates that collisions between fluids with different densities notably enhance diffusion and mixing efficiency. This has important implications for environmental science, particularly in understanding and predicting density-driven fluid dynamics in aquatic systems such as estuaries and coastal zones. The enhanced mixing efficiency observed could be crucial for applications in environmental and pollution control, offering insights into material transport and pollutant dispersion.