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Bed load transport over ripples and dunes in rivers exhibits strong spatial and temporal variability due to the complex turbulence field caused by flow separation at bedform crests. A turbulence-resolving flow model downstream of a backward-facing step, coupled with a

Bed load transport over ripples and dunes in rivers exhibits strong spatial and temporal variability due to the complex turbulence field caused by flow separation at bedform crests. A turbulence-resolving flow model downstream of a backward-facing step, coupled with a model integrating the equations of motion of individual sand grains, is used to investigate the physical interaction between bed load motion and turbulence downstream of separated flow. Large bed load transport events are found to correspond to low-frequency positive pressure fluctuations. Episodic penetration of fluid into the bed increases the bed stress and moves grains. Fluid penetration events are larger in magnitude near the point of reattachment than farther downstream. Models of bed load transport over ripples and dunes must incorporate the effects of these penetration events of high stress and sediment flux.

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    Title
    • The Role of Velocity, Pressure, and Bed Stress Fluctuations in Bed Load Transport Over Bed Forms: Numerical Simulation Downstream of a Backward-Facing Step
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    Date Created
    2015-02-09
    Resource Type
  • Text
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    Identifier
    • Digital object identifier: 10.5194/esurf-3-105-2015
    • Identifier Type
      International standard serial number
      Identifier Value
      2196-6311
    • Identifier Type
      International standard serial number
      Identifier Value
      2196-632X
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    • This article and any associated published material is distributed under the Creative Commons Attribution 3.0 License. View the article as published at: https://www.earth-surf-dynam.net/3/105/2015/

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    This is a suggested citation. Consult the appropriate style guide for specific citation guidelines.

    Schmeeckle, M. W. (2015). The role of velocity, pressure, and bed stress fluctuations in bed load transport over bed forms: numerical simulation downstream of a backward-facing step. Earth Surface Dynamics, 3(1), 105-112. doi:10.5194/esurf-3-105-2015

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