Author(s): P. Yao; M. Su; Z. B. Wang; C. K. Zhang; Y. P. Chen; M. J. F. Stive
Linked Author(s):
Keywords: Silt; High concentration layer; Near bed concentration; Flume experiment; Waves
Abstract: The sediment in a silty coast behaves different from that of a sandy coast and muddy coast. One of its distinctive characteristics is the formation of the high concentration layer (HCL) near bottom during the stormy weathers. Although this phenomenon is well known, the formation and transport mechanism is poorly understood. Historically, many theories have been proposed to describe the near bed sediment concentration for non-cohesive sediments, whether these formulations are suitable for the silt-enriched HCL is unclear. We conducted a series of flume experiments to explore this knowledge gap on the HCL of the silty coast. Two types of bed materials with different silt content are investigated. Quasisteady HCL near bottom has been reproduced in a wide range of wave conditions. The concentration inside the HCL (lowest measuring point) varies from 3 g/l to 60 g/l. Then, several existing near bed concentration predictors are tested against the experimental data. The results show that the latest formula of Van Rijn (2007a; 2007b) can give the best overall fitting and can be used as a predictor for silt range after coefficient recalibration.
Year: 2015