Density currents flowing up a slope

The dynamics of lock-release density currents propagating up a sloping bottom are investigated by Large Eddy Simulations (LES). The flow dynamics are deduced by the analysis of the density and velocity fields obtained by LES.The density current, during its propagation, is observed to develop different flowregimes: a slumping phase followed by a self-similar phase. A decrease in the velocities of the current is observed with the increase of the angle between the bottom boundary and the horizontal direction, Θ.A smoother behaviour of the current profile is also visible for high values of Θ. The presence of a backward flow close to the bottom of the domain is detected and it is found to depend on the inclination of the bottom Θ.An accumulation of dense fluid in the lock region of the tank caused by the reverse flow is also observed. Entrainment processes occurring between the ambient fluid and the dense current are observed and investigated. In particular, during the propagation of the current, light ambient fluid is entrained by the dense current, which increases in volume. It is found that the entrainment is affected by the inclination of the bottom and, in particular, a decrease of the entrainment with the increase of the steepness of the bottom is observed.