Hydraulic Structures: Fourth Edition
kbbeing the conveyance of the gross contracted section with the same normal depth and roughness characteristics as the upstream ...
Equation (10.12) is valid only if is large, i.e. the contraction cannot set up critical flow conditions between piers and choke ...
expansion losses as K2.3 m – 0.345, where m is the ratio of the obstructed and channel areas for 0.324 m0.65. (b) Discharge c ...
(c) Scour depth under the bridge If the contracted width (i.e. the bridge length, L) is less than the régime width,W(equation (9 ...
Laursen’s (1962) experimental results underestimate the scour depths, compared to many Indian experiments (Inglis, 1949) which s ...
Breusers, Nicollet and Shen (1977), Clark and Novak (1983), Richardson and Richardson (1994), Melville and Chiu (1999), Melville ...
10.2.4 Dips The dip is a shallow structure without excessive approach gradients. In arid regions, streams with infrequent flash ...
Worked Example 10.3 Establish the stage (headwater level)–discharge relationship for a concrete rectangular box culvert, using t ...
y 0 (m) Q (m^3 s^1 )(equation (i)) yc(m) 0.2 0.165 0.124 0.4 0.451 0.243 0.6 (D) 0.785 0.352 At the inlet over a short reach, H ...
H (m) Q (m^3 s^1 ) (equation (iv)) y 0 0.6 (equation (i) ← 0.691 0.723 0.72 0.805 1.00 1.364 2.00 2.487 3.00 3.242 During risin ...
yc(m) H (m) Type Q (m^3 s^1 ) 0.2 0.35 Free 0.336 0.4 0.70 Free 0.951 0.6 1.50 (1.2D) Submerged – 0.411 0.72 (1.2D) Just free ...
Solution For full pipe flow the energy equation gives H 30 0.015D0.9V^2 /2g(Vn)^2 L/R4/3V^2 /2g. (vi) Equation (vi) gives ...
10.3 Drop structures 10.3.1 Introduction A drop (or fall) structure is a regulating structure which lowers the water level along ...
10.3.2 Vertical drop structures (a) Common (straight) drop The common drop structure, in which the aerated free-falling nappe (m ...
tailwater level (TWL) is greater than the sequent depth, y 2. The following are the suggested dimensions of such a structure (Fi ...
(b) Sarda-type fall (India) This is a raised-crest fall with a vertical impact, consisting of a crest wall, upstream and downstr ...
whereVais the approach velocity. IfLeis the effective length of the crest, the head causing flow is given by the weir formula: H ...
in 3 and 1 in 8 are usually recommended. The discharge is given by the following formula: Q1.99LH3/2(H/B)1/6. (10.46) Design o ...
whereLdLd1Ld2and Ld1/Ec1.155[(P/Ec)0.33]1/2, (10.52) Ld2(D 2 dc) cot, (10.53) cotyc/Ld1. (10.54) Alternatively, the re ...
width of basin, WBV/[LB(D 2 dc)], (10.56) where the depth of the basin, dc0.1–0.3 m. 10.3.3 Inclined drops or chutes (a) Comm ...
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