The exit gradient, Ge1/6Hs/πd 2 1/2(equation (9.8)), which gives
(66/(π6))^2 3.65
and, from
1
2
[1(1^2 )1/2],
(b/d 2 )6.22;
thereforeb6.22 6 37.32 m.
382 DIVERSION WORKS
Table 9.1 Correction factors for submerged (non-modular) flows
Type of structure H 2 /H 1 f Remarks
Broad-crested weir 0.75 1.0 Upstream and downstream faces
(Ranga Raju, 1993) vertical or sloping
0.80 0.95
0.85 0.88 vertical faces
0.90 0.75
0.95 0.57
}
0.80 1
0.85 0.95 Upstream face 1:5, downstream
0.90 0.82 face 1:2
0.95 0.62
}
0.80 1
0.85 0.98 Upstream face 1:1, downstream
0.90 0.90 face 1:2
0.95 0.73
}
WES Spillway (USA) 0.3 1 P 2 /H 1 '0.75
(Chapter 4)
0.6 0.985 P 2 /H 1 0.75
0.982 1.50
0.963 2.5
0.8 0.92 P 2 /H 1 0.75
0.91 2.0
0.88 3.0
0.95 0.6 P 2 /H 1 0.75
0.55 2.0
0.45 3.0
Sharp-crested weirs:
rectangular [1 (H 2 /H 1 )3/2]0.385
triangular [1 (H 2 /H 1 )5/2]0.385
Crump weir:
Fig. 8.27
