Experimental Investigation of the Effect of Two Consecutive Obstacles on Turbidity Current

Abstract

Turbidity currents are formed when a dense fluid containing particles flows under the lighter ambient fluid because of density difference. These currents play the main role in sedimentation in dam reservoirs and lakes. Utilizing obstacles causes a rise in deposition behind them and creates a delay in entrance of the flowing particles to the outlet and power systems of reservoirs. In this work, the turbidity current behavior in the presence of two consecutive triangular obstacles is investigated experimentally. Experiments are performed in a sloped channel in different obstacle heights and inlet Froude numbers. In order to measure the velocity and concentration profiles in various stations, an Acoustic Doppler Velocimeter (ADV) is utilized. The results demonstrate that with an increase in the inlet Froude number the average velocity and concentration profiles over various obstacle heights remain approximately constant. Moreover, the amount of fluctuations between the obstacles is less than the upstream. In addition, as the obstacle height increases the amount of velocity decreases in the lower region of the current and increases in the upper zone.