Difference between revisions of "Suspended load transport"
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Sediment concentration profiles typically show a two-layer structure: | Sediment concentration profiles typically show a two-layer structure: | ||
::*'''Dilute suspension transport layer''': Far enough from the bottom, i.e. in the outer layer, the turbulence is fully-developed and the concentrations are low, typically smaller than 0.1%, corresponding to dilute conditions | ::*'''Dilute suspension transport layer''': Far enough from the bottom, i.e. in the outer layer, the turbulence is fully-developed and the concentrations are low, typically smaller than 0.1%, corresponding to dilute conditions | ||
| − | ::*'''High-concentrated (HC) suspension transport layer''': The inner layer above the bottom is characterized by low-Reynolds conditions (developing turbulence) and high concentrations. Since the inner layer usually is thin (of the order of a few centimetres), it often falls outside the depth range where measurements are collected, and therefore largely remains undetected and little known. It comprises both the [[bed load]] and the | + | ::*'''High-concentrated (HC) suspension transport layer''': The inner layer above the bottom is characterized by low-Reynolds conditions (developing turbulence) and high concentrations. Since the inner layer usually is thin (of the order of a few centimetres), it often falls outside the depth range where measurements are collected, and therefore largely remains undetected and little known. It comprises both the [[bed load]] and the sheet flow conditions for sand. Analysis of flume data suggests that particles are also kept in suspension by additional turbulence generated in the wake of the particles, which respond slower to the turbulent movements of the ambient water due to their inertia.<p> |
The transport capacity of the outer layer is controlled by that of the inner layer. | The transport capacity of the outer layer is controlled by that of the inner layer. | ||
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Revision as of 13:59, 6 September 2012
Definition of Suspended load transport:
Particles in the water column of a turbulent flow can be carried over long distances as long as the net balance between upward suspending forces and gravity remains positive.
This is the common definition for Suspended load transport, other definitions can be discussed in the article
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Sediment concentration profiles typically show a two-layer structure:
- Dilute suspension transport layer: Far enough from the bottom, i.e. in the outer layer, the turbulence is fully-developed and the concentrations are low, typically smaller than 0.1%, corresponding to dilute conditions
- High-concentrated (HC) suspension transport layer: The inner layer above the bottom is characterized by low-Reynolds conditions (developing turbulence) and high concentrations. Since the inner layer usually is thin (of the order of a few centimetres), it often falls outside the depth range where measurements are collected, and therefore largely remains undetected and little known. It comprises both the bed load and the sheet flow conditions for sand. Analysis of flume data suggests that particles are also kept in suspension by additional turbulence generated in the wake of the particles, which respond slower to the turbulent movements of the ambient water due to their inertia.
Please note that others may also have edited the contents of this article.
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