Author(s): Shu-Qing Yang
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Keywords: No Keywords
Abstract: Sediment transport is a geophysical phenomenon that sediment particles are driven t o move in streamwise and vertical directions by the corresponding forces. Many formulae ha ve been developed to predict sediment transport, and some of them have been widely used by engineers and scientists, but all of these equations do not consider the variation of force in t he vertical direction due to its difficulty, consequently, none of them is valid for problems of local scour, e.g., scour hole around a bridge pier. This study explores the importance of wallnormal velocity on sediment transport, and a new formula of sediment transport has been prop osed. The analysis shows that the wall-normal velocity is responsible for the invalidity of exis ting theorem for sediment transport including the Shields curve and Rouse equation for incipie nt motion and suspended motion of sediment, respectively. A new formula for sediment discha rge has been proposed and the unique phenomenon of “tearing bottom” observed in Yellow Ri ver is explained with the new formula.
Year: 2012