Experimental Study on the Fall Velocity of Cohesive Sediments

Abstract

Fall velocity of sediment grains affect sediment transport phenomenon significantly. In the present study some experiments were conducted in a circular flume of the Hydraulic laboratory of Shahrekord University, Iran, with 1.9 m of outer diameter. Cohesive sediment samples were taken from the North Karun watershed. Modified Krons's equation has been applied for calculating of the cohesive sediments fall velocity. In order to determine the equation's parameters, the velocity and the shear stress profile and sediment concentration were measured at various times for each experiment. The results showed that increasing in concentration causes the fall velocity of the sediments to be decreased. It denotes inverse correlation between sediment concentration and fall velocity. Finally, based on the obtained results of this study an equation was obtained to calculate the cohesive sediments fall velocity.

Keywords

• cohesive sediments
• annular flume
• fall velocity
• shear stress