Author(s): P. J. Rusello; E. A. Cowen

Linked Author(s): Edwin Cowen

Keywords: No Keywords

Abstract: One of the basic goals of most cohesive sediment transport studies is the determination of erosion rate (E) as a function of the applied bed stress (). Previous laboratory experiments have been conducted in annular and linear re-circulating flumes (e.g., SEDFLUME) to measure erosion rate as a function of depth in a sediment core. In these experiments, the applied bed stress was determined independently of erosion tests through either measurements over an impermeable bed or estimated from hydraulic flow theory. A calibration curve for each experimental facility is developed relating applied bed stress and flume settings. However, there is a history of literature detailing turbulent drag reduction by additives meaning that these calibrated facilities are biased by utilizing a bed stress estimate made with no additives. Similarly, because of the lack of detailed flow measurements, the calibrated facilities provide little insight into the underlying physics and turbulent flow effects on cohesive sediment erosion. In experiments conducted in an 8 m linear recirculating flume, we utilize quantitative imaging techniques to simultaneously measure the mean velocity profile, turbulent velocities and higher order statistics, bed level, and suspended sediment concentration over an erosion test section. By analyzing the detailed velocity field data, insight into the resuspension process and an estimate of the bias in bed stress estimates due to boundary layer modifications are made.

DOI:

Year: 2009