About the specification of erosion flux for soft stratified cohesive sediments

Autor: André Temperville, Y. Peter Sheng, Georges Chapalain
Rok vydání: 1994
Předmět:
Zdroj: Mathematical Geology. 26:651-676
ISSN: 1573-8868
0882-8121
DOI: 10.1007/bf02086866
Popis: The present paper deals with the specification of bed erosion flux that accounts for the effects of sediment-induced stratification in the water column. Owing to difficulties in measuring the bed shear stress τb and the erosive shear strength τs, we suggest a series of methods that combine laboratory and numerical experiments. A simplified turbulent transport model that includes these effects helps to quantify τb and τs. Focusing on soft stratified beds, the present study considers erosion rate formulas of the form e=ef exp {[Tb-Tsα]β} where β is a model constant (β=1 for Gularte's (1978) formula and β=1/2 for Parchure's (1984) formula). First, the bed erosive strength profile τs(Z) is adjusted by “forcing” the turbulent transport model with measured erosion rates. Second, three procedures are suggested to determine the erosion rate formula coefficients ef and α: a global procedure and two different layer-by-layer procedures. Each procedure is applied to an erosion experiment conducted in a rotating annular flume by Villaret and Paulic (1986). The use of the layer-by-layer procedure based on a least squares fitting technique provides a closer fit than the global procedure. The present study points out the complementarity of experimental and numerical approaches and also suggests possible improvements in laboratory test procedures.
Databáze: OpenAIRE
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