Helicoidal flow is the cork-screw-like flow of
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...
in a
meander
A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex ban ...
. It is one example of a
secondary flow
In fluid dynamics, flow can be decomposed into primary plus secondary flow, a relatively weaker flow pattern superimposed on the stronger primary flow pattern. The primary flow is often chosen to be an exact solution to simplified or approximated ...
.
Helicoidal flow is a contributing factor to the formation of
slip-off slopes and
river cliff
A cut bank, also known as a river cliff or river-cut cliff, is the outside bank of a curve or meander in a water channel ( stream), which is continually undergoing erosion.Essentials of Geology, 3rd Ed, Stephen Marshak Cut banks are found in ab ...
s in a meandering section of the river. The helicoidal motion of the flow aids the processes of
hydraulic action
Hydraulic action, most generally, is the ability of moving water (flowing or waves) to dislodge and transport rock particles. This includes a number of specific erosional processes, including abrasion, at facilitated erosion, such as ''static eros ...
and
corrasion
Corrasion is a geomorphological term for the process of mechanical erosion of the earth's surface caused when materials are transported across it by running water, waves, glaciers, wind or gravitational movement downslope. An example is the weari ...
on the outside of the meander, and sweeps sediment across the floor of the meander towards the inside of the meander, forming
point bar deposits.
[
]
See also
*
Laminar flow
In fluid dynamics, laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral mi ...
*
Turbulent flow
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between t ...
*
Baer's law
*
Secondary flow in river bends
References
Bibliography
Journal of Geophysical Research, Volume 107 (2002)
Rivers
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