非恒定流驱动下床面形态变化特征

TY - JOUR

T1 - 非恒定流驱动下床面形态变化特征

AU - Wang, Le

AU - Cuthbertson, Alan J. S.

AU - Zhang, Shanghong

AU - Wang, Yongqiang

N1 - Funding Information: This study is financially supported by the National Natural Science Foundation of China (No.52009041; No.52061135104). Publisher Copyright: © 2021, Editorial Board of Advances in Water Science. All right reserved.

PY - 2021/9/30

Y1 - 2021/9/30

N2 - The main objective of this study is to investigate the morphological response and variability in the wavelength, height, steepness of bed forms developed over a quasi-uniform, coarse-sand bed under unsteady flows, with zero sediment feed condition specified at the upstream boundary. A series of smooth, bell-shaped hydrographs are generated within a titling flume, each defined parametrically by their shape (η), unsteadiness (ΓHG) and total water work (Wk). By contrast, the bed forms generated in the sediment bed are quantified through their wavelength (λ), height (D) and steepness (ψ). Experimental results indicate that different categories of bed forms, such as dunes, alternate bars, or transitional structures, developed on the bed surface over the hydrograph duration. A close examination of relative importance of three hydrograph's parameters (i.e. η, ΓHG and Wk) on bed-form dimensional descriptors (i.e. λ, D, ψ) reveals that the flow unsteadiness and total water work appear to be the primary and second-order control on bed-form category developed and their overall magnitude, whereas the hydrograph shape (η) appears to have a minimal impact. Based on this knowledge, a constitutive model to describe the effect of unsteady flow hydrographs on the bed-form categories and magnitude is developed from the results in the present study.

AB - The main objective of this study is to investigate the morphological response and variability in the wavelength, height, steepness of bed forms developed over a quasi-uniform, coarse-sand bed under unsteady flows, with zero sediment feed condition specified at the upstream boundary. A series of smooth, bell-shaped hydrographs are generated within a titling flume, each defined parametrically by their shape (η), unsteadiness (ΓHG) and total water work (Wk). By contrast, the bed forms generated in the sediment bed are quantified through their wavelength (λ), height (D) and steepness (ψ). Experimental results indicate that different categories of bed forms, such as dunes, alternate bars, or transitional structures, developed on the bed surface over the hydrograph duration. A close examination of relative importance of three hydrograph's parameters (i.e. η, ΓHG and Wk) on bed-form dimensional descriptors (i.e. λ, D, ψ) reveals that the flow unsteadiness and total water work appear to be the primary and second-order control on bed-form category developed and their overall magnitude, whereas the hydrograph shape (η) appears to have a minimal impact. Based on this knowledge, a constitutive model to describe the effect of unsteady flow hydrographs on the bed-form categories and magnitude is developed from the results in the present study.

KW - Bed forms

KW - Flood

KW - Unsteady flow

UR - https://www.scopus.com/pages/publications/85115790516

U2 - 10.14042/j.cnki.32.1309.2021.05.010

DO - 10.14042/j.cnki.32.1309.2021.05.010

M3 - Article

AN - SCOPUS:85115790516

SN - 1001-6791

VL - 32

SP - 751

EP - 758

JO - Shuikexue Jinzhan/Advances in Water Science

JF - Shuikexue Jinzhan/Advances in Water Science

IS - 5

ER -