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Unformatted text preview: y motions similar to Fig. 6.16 for closedduct flows. If the channel curves or
meanders, the secondary motion intensifies due to centrifugal effects, with high velocity occurring near the outer radius of the bend. Curved natural channels are subject
to strong bottom erosion and deposition effects. The OneDimensional
Approximation 0.5 2.0
1.5 2.0 1.5 1.0 1.0 0.5 Trapezoidal channel
Triangular channel 2.0 0.5
1.5 1.0 2.5
2.0
0.5 Shallow ditch 1.5 1.0 Pipe 2.5
2.0 1.0  v v Fig. 10.1 Measured isovelocity
contours in typical straight openchannel flows. (From Ref. 3.) 2.5 1.5 1.5 1.0 0.5 2.0 0.5 Natural irregular channel  eText Main Menu  Textbook Table of Contents Narrow rectangular section  Study Guide 10.1 Introduction 661 b0
y
V Fig. 10.2 Geometry and notation
for openchannel flow: (a) side
view; (b) cross section. All these
parameters are constant in uniform
flow. A y θ
S = tan θ Horizontal x P (a) Rh = A
P (b) With the advent of the supercomputer, it is possible to make numerical simulations
of complex flow patterns such as in Fig. 10.1 [23]. However, the practical engineering...
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 Spring '08
 Sakar

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