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Classification of channels
Channels can be classified as:
1.Prismatic channels and non-prismatic channels
2.Natural and Artificial channels
3.Rigid boundary and mobile boundary channel
A channel is said to be prismatic channel if the cross-section and bed slope does not change along the length of the channel.
Example: A laboratory flume laid at a constant bed slope and uniform cross-section.
A channel is said to be non-prismatic channel if there is a change in cross-section and bed slope along the length of the channel.
Example: A river with varying cross-section and bed slope.
Rivers and streams are natural channels. Natural channels have the irregular cross-section. So it is difficult to define the flow depth for natural channels.
Human-made channels are called artificial channels. Irrigation Canals, sewage pipes, aqueducts etc. are examples of artificial channels. Artificial channels have regular cross-sections like triangular, trapezoidal, rectangular, circular etc.
Rigid Boundary channel
A channel is said to be a rigid boundary channel if the material on the bed and sides of a channel is not easily movable.
Example: concrete lined canal, a metal flume.
Mobile Boundary channel
A channel is said to be a mobile boundary channel if the material on the bed and sides of a channel is loose and easily movable due to the flow of water. Analysis of mobile boundary channel is more complicated due to sediment erosion, deposition and resulting in additional resistance to flow.
Book- Fluid Mechanics(Hydraulics), Writer- A.K. Upadhyay