Section
44 33 22 11
Width (m) 25.00 12.50 12.50 25.00
Area of flow (m^2 ) 56.00 25.00 25.00 56.00
Velocity (m s^1 ) 0.536 1.20 1.20 0.536
Losses (m) (expansion) (friction) (contraction)
0.017 0.017 0.012
Water surface level
(m AOD) 202.000 201.959 201.976 202.406
Velocity head (m) 0.015 0.073 0.073 0.015
TEL (m AOD) 202.015 202.032 202.049 202.061
Flow depth (m) 2.00 2.00 2.00 2.00
Bed level (m AOD) 200.00 199.959 199.976 200.046
Note that the contraction loss0.2(V^22 V^21 )/2g; the expansion loss0.3
(V^23 V^24 )/2g; the flume friction lossV^2 fn^2 Lf/R4/3f (the suffix f denotes the
flume, and o the original canal – VfV 3 V 2 ;VoV 4 V 1 ).
DESIGN OF TRANSITIONS
For a constant depth of flow the transition may be designed such that the
rate of change of velocity per metre length of transition is constant. This
approach yields the bed width of the transition at a distance xfrom the
flume section as
BxBoBfL/[LBo (Bo Bf)x]
422 CROSS-DRAINAGE AND DROP STRUCTURES
Fig. 10.3 Transition with cylindrical inlet and linear outlet. LcandLeare
contraction and expansion lengths
