Sunday, April 10, 2011

HHM - Classification of Bed Slope Profiles


Open channels are classified as being mild, steep, critical, horizontal, and adverse in gradually-varied flow studies. If for a given discharge the normal depth of a channel is greater than the critical depth, the channel is said to be mild. If the normal depth is less than the critical depth, the channel is calledsteep. For a critical channel, the normal depth and the critical depth are equal. If the bottom slope of a channel is zero, the channel is called horizontal. A channel is said to have an adverse slope if the channel bottom rises in the flow direction. In summary:

Mild channels

y n > y c

Steep channels

y n < y c

Critical channels

y n = y c

Horizontal channels

S 0 = 0

Adverse channels

S 0 < 0

where y n = normal depth and y c = critical depth.

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