H Flumes - nptel - Indian Institute of Technology Madras

Hydraulics Prof. B.S. Thandaveswara
H Flumes
In natural streams the range of discharge varies widely and a structure with a V-type
control has an advantage of providing wide opening at high flows causing less back
water effect and for low discharges its opening reduced so that the sensitivity of the
structure is in acceptable range.
US.SCS has developed the H type flumes namely
HS- (Small flumes), H- (normal flumes) and HL- (large) size flumes.
Small flume has a maximum size of 305 mm height and has a
Indian Institute of Technology Madras
max
3 -1
Q = 0.022m s .
Normal flume has a maximum size of 1370 mm and a capacity of 2.36 m 3 s -1 . On the
other hand large flumes have 1370 mm depth but the discharge capacity of 3.32 m 3 s -1 .

Hydraulics Prof. B.S. Thandaveswara
1.5 D
Indian Institute of Technology Madras
D
0.05 D
1.05 D
Well
opening
0.383 D
6
1
1
3
Plan
D
1.897
1.05 D 1.5 D
Front and Side elevations of HS flume
1
1
2
D

Hydraulics Prof. B.S. Thandaveswara
3
2
Indian Institute of Technology Madras
1.9 D
0.1 D
2
1
1.1 D
1.9 D
1.35 D
D
Front and side elevations
H normal flume
3
4
0.6 D
1.35 D
Well opening
0.3 D

Hydraulics Prof. B.S. Thandaveswara
1.25 D1.5 D
Indian Institute of Technology Madras
0.2 D
3.2 D
1
1
D 1
1
HL (Large) flume
1.5 D
Front and side elevations
0.5 D
Typical dimensions of H-type flumes
Figure shows the details of flumes.
In practice these are constructed using sheet metal or suitable material.
The discharge equation is of the form
( ) 2
log Q = A +B log h a + C log h a
0.25 D
Well openings
in which ha is the upstream head, A, B, C are the constants. The error is expected to be
less than 3%.
V
The Froude number = 1 should not exceed 0.5
A
g 1
T