Author(s): Peter K. Stansby; M.A. Omar Awang

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Abstract: The way in which sediment characteristics and water depth determine the time taken for suspended sediment concentration profiles to approach a steady state has been investigated. The idealised situation of a bed of sediment in a steady current with initially clear water is considered. Analytical solutions are inferred from previous work and a numerical scheme with a particular vertical mesh transformation has been found to be effective. Response time, tr however non-dimensionalised, is generally dependent on the Rouse parameter,y, and the particle size to depth ratio, dlh. For y > 1 however, t,u∗ld depends only on y, where u∗, is the friction velocity. It is also shown that trws/h, where ws is the fall velocity, is always less than about 2.4, at least for dlh ≥ 10-6, the smallest value investigated. The numerical scheme is used to compare with some experimental measurements of nonequilibrium sediment transport in a steady current to confirm some of the physical modelling assumptions.

DOI: https://doi.org/10.1080/00221689809498622

Year: 1998