The Rouse number (P or Z) is a
non-dimensional number in
fluid dynamics
In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in motion ...
which is used to define a concentration profile of
suspended sediment and which also determines how
sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
will be transported in a flowing fluid. It is a ratio between the sediment
fall velocity and the upwards velocity on the grain as a product of the
von Kármán constant and the
shear velocity .
:
Occasionally the factor β is included before the von Kármán constant in the equation, which is a constant which correlates eddy viscosity to eddy diffusivity. This is generally taken to be equal to 1, and therefore is ignored in actual calculation. However, it should not be ignored when considering the full equation.
:
It is named after the
American fluid dynamicist
Hunter Rouse. It is a characteristic scale parameter in the
Rouse Profile of suspended sediment concentration with depth in a flowing fluid. The concentration of suspended sediment with depth goes as the power of the negative Rouse number. It also is used to determine how the particles will move in the fluid. The required Rouse numbers for transport as
bed load,
suspended load
The suspended load of a flow of fluid, such as a river, is the portion of its sediment uplifted by the fluid's flow in the process of sediment transportation. It is kept suspended by the fluid's turbulence. The suspended load generally consists ...
, and
wash load, are given below.
See also
*
Sediment transport
*
Sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
*
Dimensionless quantity
Dimensionless quantities, or quantities of dimension one, are quantities implicitly defined in a manner that prevents their aggregation into unit of measurement, units of measurement. ISBN 978-92-822-2272-0. Typically expressed as ratios that a ...
References
* Whipple, K. X (2004), 12.163 Course Notes, MIT Open Courseware
Dimensionless numbers of physics
Fluid dynamics
Sedimentology
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