The Influence of Slipface Angle on Fluvial Dune Growth
| Autor: | David Hurther, Suleyman Naqshband, A.J.F. Hoitink, Sanjay Giri, Jeremy G. Venditti, Ray Kostaschuk, Ryan W. Bradley |
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| Přispěvatelé: | Wageningen University and Research [Wageningen] (WUR), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Deltares [The Netherlands] |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
WIMEK
010504 meteorology & atmospheric sciences Turbulence Flow (psychology) Fluvial Sediment 010502 geochemistry & geophysics Hydrology and Quantitative Water Management 01 natural sciences Flow separation Geophysics Flow velocity Life Science [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] Sediment transport Geomorphology Geology ComputingMilieux_MISCELLANEOUS 0105 earth and related environmental sciences Earth-Surface Processes Bed load Hydrologie en Kwantitatief Waterbeheer |
| Zdroj: | Journal of Geophysical Research: Earth Surface, 126(4) Journal of Geophysical Research: Earth Surface Journal of Geophysical Research: Earth Surface, American Geophysical Union/Wiley, 2021, 126 (4), ⟨10.1029/2020JF005959⟩ Journal of Geophysical Research: Earth Surface 126 (2021) 4 |
| ISSN: | 2169-9003 2169-9011 |
| DOI: | 10.1029/2020JF005959⟩ |
| Popis: | Dunes dominate the bed of sandy rivers and they respond to flow by changing shape and size, modifying flow, and sediment transport dynamics of rivers. Our understanding of and ability to predict dune adaptation, particularly dune growth and decay, remain incomplete. Here, we investigate dune growth from an initial flatbed in a laboratory setting by continuously mapping the 3D bed topography using a line laser scanner combined with a 3D camera. High-resolution profiles of flow velocity and sediment concentration providing both bedload and suspended sediment fluxes were obtained by deploying Acoustic Concentration and Velocity Profiler technology. Our analysis reveals that the magnitude of the dune slipface angle, which determines flow separation and controls turbulence production, adjusts to the imposed flow at time scales similar to the evolution of dune height and length. The initiation of a flow separation zone intensifies through scour, and results in acceleration of the dune growth. Gradients in sediment transport and the rate of dune growth are inherently linked to spatial variations in slipface angles. During dune growth, the slipface angle evolves differently than the ratio of dune height to length, which immediately reaches its equilibrium value after dune initiation. |
| Databáze: | OpenAIRE |
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