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Published on: January 17, 2012
Width of laminar laboratory rivers
G Seizilles1, O Devauchelle, E Lajeunesse
1Institut de Physique du Globe de Paris, 1 rue Jussieu, 75238 Paris cedex 05, France.
Summary
Viscous fluid flow over plastic grains forms stable, single-thread channels. These laboratory rivers follow the threshold hypothesis, demonstrating a link between granular avalanches and sediment transport criteria.
Area of Science:
- Fluid Dynamics and Geomorphology
- Granular Physics
Background:
- Flowing viscous fluids over granular beds can spontaneously form channels.
- These channels, analogous to alluvial rivers, can reach a steady state with reproducible dimensions.
Purpose of the Study:
- To investigate the formation and steady-state characteristics of single-thread channels in a viscous fluid-granular system.
- To test the applicability of the threshold hypothesis in explaining channel morphology in the absence of sediment transport.
- To explore the relationship between granular material behavior and sediment transport criteria.
Main Methods:
- Experimental setup involving a viscous fluid flowing over plastic grains.
- Observation and measurement of channel formation, width, and cross-section over time.
- Analysis of channel morphology in relation to fluid discharge and granular properties.
Main Results:
- Spontaneous generation of single-thread channels observed.
- Channels reached a reproducible steady state with well-defined width and cross-section.
- Channel shape aligned with the threshold hypothesis in the absence of sediment transport.
Conclusions:
- The threshold hypothesis successfully explains channel size and slope selection for a given discharge in this system.
- Laboratory rivers provide a model to illustrate the connection between granular avalanche angles and Shields's criterion for sediment transport.
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