Submitted to: Trans American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 12/15/1998
Publication Date: N/A
Technical Abstract: Processes of transverse mixing in rivers remain an important aspect of point-source effluent dispersal, interactions of fluid and sediment at tributary junctions, and overbank sediment deposition on floodplains. Understanding such processes is critically important in the design of suspended sediment sampling programs, in data interpretation, and in testing new suspended sediment measurement technology. In the absence of channel curvature and bed topography, distribution of suspended sediment in the transverse direction has been linked to the gradient diffusion of turbulence via the classical eddy viscosity concept. An experimental study was initiated to identify and quantify the lateral and temporal variability of suspended sediment concentration and turbulent flow structure over a mobile upper-stage plane bed, and to address the contribution of turbulent convective motions to transverse fluxes of suspended sediment. A dual-nozzle isokinetic pump sampling system, acoustic Doppler velocimeter, electromagnetic current meter, optical backscatter probe, and acoustic bed height probes were used to collect concomitant data on turbulent flow, suspended sediment flux, and bed topography. Results will be presented describing the distribution of sediment concentration across the flume, time series analysis correlating turbulent velocity fluctuations and sediment flux, and the impact of low relief bed waves on the transverse and temporal variations of suspended sediment concentration.