Experimental investigation of the effect of salt wedge on concentration of suspended non-cohesive particles in turbid flow

Abstract

To have an insight of the effects of salt wedge on suspended sediment concentration (SSC), we carried out experiments of intruding salt wedge in flume with fresh turbid water of non-cohesive particles and salt water free of sediment. Two sets of Acoustic Doppler Velocity Profiler (ADVP) were used to record instantaneous velocity profiles in the saline affected zone near the bed. The acoustic back scattered signal amplitudes (AMP) in the measurements were used to estimate SSC at the same point and the same time. The results show that around the interface shear of exchange flow is remarkable and SSC increases noticeably. Flow analysis indicates that large scale turbulence from interfacial instability is the main power source to enhance sediment carrying capacity of the flow. It weakens and retards the particles in the upper turbid layer sinking to the lower saline zone. However, the energy dissipation doesn’t show much change.