ENGG 2230 Lecture Notes - Lecture 19: Open-Channel Flow, Wetted Perimeter, Free Surface
28 Nov 2017
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Document Summary
With a free surface we"re allowed to take the pressure anywhere along the surface as atmosphere: free surface becomes the hydraulic grade line, pressure gradient is not a driving force as in pipe flow. Free surface complicates things a bit since the shape is not known beforehand. Open channel flow will always have a wetted perimeter and satisfy a no slip condition. Often assume a one dimensional approximation such that incompressible continuity equation can be applied. Apply the energy equation between point 1 (upstream) and point 2 (downstream: z is the total elevation of the free surface including the depth of the water (y) plus the height of the sloping bottom.
