Experimental study of turbidity currents flow around obstacles

Abstract

In artificial and natural reservoirs, turbidity currents can be an important mechanism for transporting fine sediments to the deepest area of the reservoir, where they settle. A solid obstacle can be placed at the bottom of the reservoir to partially block or divert the turbidity current flow preventing the deposition of sediments near intakes and other structures. A series of experiments were undertaken to investigate the influence of obstacles on turbidity currents flow dynamics, in particular, in the currents vertical velocity profiles and front velocity. Two series of laboratory tests with different obstacle heights were carried out in a channel 16.45 m long and 0.30 m wide with variable bottom slopes. To generate the turbidity currents a mixture of water and silica flour was used, considering different initial values of suspended sediments concentration. The results showed a reduction of the front velocity with the increasing obstacle height while the characteristic ratios of the velocity profiles remained constants.