Gravity Currents Propagating on Sloping Boundaries

Abstract

AbstractThree-dimensional direct numerical simulations of gravity currents on different bottom slopes are presented in this paper. After the buoyancy closed in a lock is instantaneously released, the produced gravity currents go through an acceleration phase followed by a deceleration phase. In the acceleration phase, the tail current connects to and feeds buoyancy into the head for all cases considered here. The maximum buoyancy contained in the head, reached at the end of the acceleration phase, increases as the bottom slope increases. The maximum buoyancy in the head never reaches the total released buoyancy, and a significant portion of released heavy fluid is left in the tail current. In the deceleration phase, the tail current continues to join the head as the gravity currents propagate for lower slope angles (θ=0.2, and 4°), but the head disconnects the joining tail current for higher slope angles (θ=6, 8, and 10°). The gravity current head loses contained buoyancy less rapidly in the deceleration ...