Geomorphic implications of gravity currents created by changing initial conditions

Abstract. Gravity currents reproduced in laboratory by the lock-exchange technique are here tested for three initial densities and five lock-lengths, for horizontal and four inclinations of the lock. The main purpose is to quantify the effect of the increment of gravitational forces, due to the introduction of a slope, on the hydrodynamics of gravity currents and consequently on its transport capacity. The shape of the current is altered due to the enhanced entrainment of ambient water and mainly the body of the current results affected. A range of slopes is tested, going from horizontal to a limit case in which two mechanisms compete, i.e. the current entrainment of water from the upper surface due to the increment of friction and the head feeding by the rear steady current. In particular, bed shear stress and the corresponding geomorphic potential are analyzed. Using a base experience where erosion of a mobile bed was investigated, the implications of an inclined lock in the entrainment capacity of the flow is here discussed.