DOI: 10.1002/2014GL060906
论文题名: Effect of bed permeability and hyporheic flow on turbulent flow over bed forms
作者: Blois G. ; Best J.L. ; Sambrook Smith G.H. ; Hardy R.J.
刊名: Geophysical Research Letters
ISSN: 0094-9789
EISSN: 1944-9520
出版年: 2014
卷: 41, 期: 18 起始页码: 6435
结束页码: 6442
语种: 英语
英文关键词: bed forms
; coarse sediments
; hyporheic flow
; morphodynamics
; permeability
; turbulence
Scopus关键词: Mechanical permeability
; Morphology
; Reynolds number
; Stream flow
; Turbulence
; Bed forms
; Biogeochemical cycling
; Coarse sediment
; Hyporheic
; Modeling and predictions
; Morphodynamics
; Particle imaging velocimetry
; Sediment entrainments
; Sediments
; bedform
; coarse woody debris
; geomorphology
; hyporheic zone
; morphodynamics
; permeability
; Reynolds number
; turbulent flow
英文摘要: This paper uses particle imaging velocimetry to provide the first measurements detailing the flow field over a porous bed in the presence of bed forms. The results demonstrate that flow downstream of coarse-grained bed forms on permeable beds is fundamentally different to that over impermeable beds. Most significantly, the leeside flow separation cell is greatly modified by jets of fluid emerging from the subsurface, such that reattachment of the separated flow does not occur and the Reynolds stresses bounding the separation zone are substantially lessened. These results shed new light on the underlying flow physics and advance our understanding of both ecological and geomorphological processes associated with permeable bed forms. Water fluxes at the bed interface are critically important for biogeochemical cycling in all rivers, yet mass and momentum exchanges across the bed interface are not routinely incorporated into flow models. Our observations suggest that ignoring such exchange processes in coarse-grained rivers may overlook important implications. These new results also provide insight to explain the distinctive morphology of coarse-grained bed forms, the production of openwork textures in gravels, and the absence of ripples in coarse sands, all of which have implications for modeling and prediction of sediment entrainment and flow resistance. Key Points Wall permeability allows mass and momentum exchanges at the interfaceSubsurface-surface flow exchange modifies flow structure in the bed form leesideEffects of permeability on morphology of coarse-grained bed forms ©2014. The Authors. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911092248&doi=10.1002%2f2014GL060906&partnerID=40&md5=1488b9e01559c22c0e82e1144091bd92
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/7053
Appears in Collections: 气候减缓与适应
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作者单位: Department of Geology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
Recommended Citation:
Blois G.,Best J.L.,Sambrook Smith G.H.,et al. Effect of bed permeability and hyporheic flow on turbulent flow over bed forms[J]. Geophysical Research Letters,2014-01-01,41(18).