Fluvial and submarine morphodynamics of laminar and near-laminar flows: a synthesis

Lajeunesse, É.; Malverti, L.; Lancien, Pierre; Armstrong, Lawrence E.; Métivier, François; Coleman, Stephen E.; Smith, Charles E.; Davies, Timothy R. H.; Cantelli, Alessandro; Parker, Gary

doi:10.1111/j.1365-3091.2009.01109.x

Cited by 56 publications

(48 citation statements)

References 52 publications

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“…While, in most of the natural occurrence of these patterns, the flow is likely turbulent, it is not necessary and laminar flows also generate such features. The similarity in observed morphologies seem to reflect analogies in the underlying physics and thus using laminar flow can be a simplest way in the laboratory to obtain insights into many aspects of sediment transport and morphodynamics (Lajeunesse et al 2010). The present paper focusses on particle transport in the laminar regime and in particular on the mode of particle motion in which particles roll and slide but stay in continuous contact within the bed, a situation usually referred to as 'bedload' transport (see e.g.…”

Section: Introductionmentioning

confidence: 93%

Investigation of the mobile granular layer in bedload transport by laminar shearing flows

et al. 2013

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The mobile layer of a granular bed composed of spherical particles is experimentally investigated in a laminar rectangular-channel flow. Both particle and fluid velocity profiles are obtained using particle image velocimetry for different index-matched combinations of particles and fluid and for a wide range of fluid flow-rates above incipient motion. A full three-dimensional investigation of the flow field inside the mobile layer is also provided. These experimental observations are compared to the predictions of a two-phase continuum model having a frictional rheology to describe particle-particle interactions. Different rheological constitutive laws having increasing degree of sophistication are tested and discussed.

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Section: Introductionmentioning

confidence: 93%

Investigation of the mobile granular layer in bedload transport by laminar shearing flows

et al. 2013

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“…The difference between the laboratory and field flows, however, does not invalidate the usefulness or applicability of the experiments. Indeed, Lajeunesse et al (2010) have shown that most of the morphodynamics of rivers can be captured at laminar scale or near-laminar scale, including self-formed channels, dunes, antidunes, bars, and meandering. Even though such experiments are not precise scale models of the field, it is found that a number of features scale remarkably well.…”

Section: J S Rmentioning

confidence: 99%

Growth Patterns of Subaqueous Depositional Channel Lobe Systems Developed Over A Basement With A Downdip Break In Slope: Laboratory Experiments

Fernandez

Cantelli

Pirmez

et al. 2014

Journal of Sedimentary Research

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A series of large-scale experiments on nonchannelized, depositional turbidity currents show the evolution and complex stratigraphy of channel-lobe systems developed updip and downdip of a break in slope. Two different sets of experimental turbidity currents with different sediment concentrations were run. The results provided a comparative picture of the gross structure of the fans, with information on their surfaces, growth sequences, and times of activity of the incised channels and lobed features. In particular, data analysis focused on: (a) velocity and suspended-sediment concentration of the flows themselves; (b) time and spatial sequences of channel and lobe construction and modification, and (c) spatial trends in grain-size distribution along the deposit. Significantly, the floor geometry employed in this study allowed investigation of adjustments in deep-sea fan deposition associated with natural changes in bed slope. We show here that the break in slope played a very important role in governing channel aggradation and lobe architecture over the deposit. More specifically, the slope break tended to break up the formation of long channels and enhance the formation of lobate features. A comparison with field submarine lobe analogs demonstrates that the morphodynamics and stratigraphy associated with lobed fans can indeed be modeled, within limits, at laboratory scale.

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“…Natural braided rivers are fully turbulent; flood flows can be supercritical, but Froude numbers are typically closer to 1 [3]. However, the dynamics of channels relevant to evolution of the river system are insensitive to the modest influence that Reynolds and Froude numbers exert on time-averaged grainscale transport [32][33][34][35]. More important is the dimensionless fluid shear (Shields) stress, which controls the mode and rate of sediment transport within the channels.…”

Section: Methodsmentioning

confidence: 99%

Diffusive evolution of experimental braided rivers

et al. 2014

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Water flowing over a loose granular bed organizes into a braided river, a network of ephemeral and interacting channels. The temporal and spatial evolution of this network of braided channels is not yet quantitatively understood. In ∼1 m-scale experiments, we found that individual channels exhibit a self-similar geometry and near-threshold transport conditions. Measurements of the rate of growth of topographic correlation length scales, the time scale of system-slope establishment, and the random spatial decorrelation of channel locations indicate together that the evolution of the braided river system may be diffusive in nature. This diffusion is due to the separation of scales between channel formation and network evolution, and the random motion of interacting channels when viewed at a coarse-grained scale. Water flowing over a loose granular bed organizes into a braided river, a network of ephemeral and interacting channels. The temporal and spatial evolution of this network of braided channels is not yet quantitatively understood. In ∼ 1 m-scale experiments, we found that individual channels exhibit a self-similar geometry and near-threshold transport conditions. Measurements of the rate of growth of topographic correlation length scales, the time scale of system-slope establishment, and the random spatial decorrelation of channel locations indicate together that the evolution of the braided river system may be diffusive in nature. This diffusion is due to the separation of scales between channel formation and network evolution, and the random motion of interacting channels when viewed at a coarse-grained scale.

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Fluvial and submarine morphodynamics of laminar and near-laminar flows: a synthesis

Cited by 56 publications

References 52 publications

Investigation of the mobile granular layer in bedload transport by laminar shearing flows

Investigation of the mobile granular layer in bedload transport by laminar shearing flows

Growth Patterns of Subaqueous Depositional Channel Lobe Systems Developed Over A Basement With A Downdip Break In Slope: Laboratory Experiments

Diffusive evolution of experimental braided rivers

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