Author(s): Jiang Yu; Fengguang Yang; Yue Liang
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Keywords: Natural sediment; Settling velocity; Error; Compare
Abstract: Sediment settling velocity reflects the resistance of the mechanical movement when the sediment interacts with the flow. Therefore, the research of sediment movement and hydraulic computation is often related to the sediment settling velocity. However, there are so many settling velocity formulae for natural sediment that it is very hard to choose in engineering computation. So it is necessary to evaluate the precision of the formulae to solve the practical problems of sediment engineering better. This study provides a quantitative assessment of five sediment settling velocity formulae which were selected from the collection of on-hand literature by comparing them to experimental data. In all, 169 data were selected using for comparison which contained 43 runs by Cheng (1997), 13 runs by Raudkivi (1990), 4 runs by Dalrymple and Thompson (1976), 22 runs by England and Hansen (1967), 2 runs by Gurley (1980), 36 runs by Hottocvy and Sylvester (1979), 3 runs by MacDonald (1977), 19 runs by Maginot (1977), 7 runs by Nyack (1970), 2 runs by Nicholson (1968), 5 runs by Nielsen (1979), 3 runs by Rouse (1938), 2 runs by Shinohara et al. (1959), and 8 runs by Vincent (1958) etc. Results show that the formula of Cheng (1997) gives the best prediction by comparing the computed result of every formula with the experiments, whose error range is from 0. 158% to 23. 4% and average relative error is 6. 223% . The formula of Rubbery (1993) gives the worst prediction with its error ranges from 1. 53% to 63. 4% and average relative error is 26. 026% . The formulae precision of Ruijin Zhang (1989), Yuqing Sha (1956), Wachilough（1962）decrease in turn.
Year: 2013