Hydraulic Structures: Fourth Edition

(Amelia) #1

Worked Example 10.2


Design an expanding transition for the flume–canal layout of worked
example 10.1 using the Vittal and Chiranjeevi (1983) method.


Solution


Design discharge30 m^3 s^1 ; bed width of canal, Bo25 m; bed width
of flume, Bf12.5 m; side slope of canal, mo1.50; bed level of
canal200.00 m AOD; depth of flow in canal, yo2 m (Worked example
10.1). Length of transition, L2.35(25 12.5)1.651.5 2 ≈36 m. Bed
width in transition, Bx, with n0.8 0.26(1.5)1/20.482,


Bx12.5(12.5x/36)[1 (1 x/36)0.482].

Side slope in transition,


m1.5[1 (1 x/36)1/2].

The complete set of calculations is presented in the table below:


Number Distance from upstream yx(m) m Bx(m) ∆z Bed elevation
end of transition, x (m) (m) (m AOD)


1 36 2.000 1.50 25.000 200.000
2 27 1.985 0.75 17.069 0 200.000
3 18 1.965 0.44 15.737 0.001 199.999
4 09 1.950 0.20 12.545 0.002 199.998
5 00 1.935 0 12.500 0.003 199.997


AQUEDUCTS AND CANAL INLETS AND OUTLETS 427


Fig. 10.5 Longitudinal section of the siphon aqueduct; all dimensions in
metres

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