Test: Flow Over Notches & Weirs

For ogee spillway, C_d1 = 1.19 C_ds
Cds is the discharge coefficient for sharp - crested weir. So 4 will come after 3.
The classification of weir is:

Further submerged weirs have lesser coefficient of discharge compared to free weirs. So, 2 will come after 1.

(i) Rehbock’s formula is an empirical formula for calculating discharge in rectangular suppressed weir. It is given by,

Where L is the length of weir, H is head in meters and Z is the crest height in meters,
(ii) Francis’ formula is one of the commonly used empirical formula for computing the discharge over sharp or narrow crested weirs with or without end contraction. Francis proposed the following formulae for the discharge over rectangular weir.
(a) When the velocity of approach is not considered, 
Q = 1.84(L - 0.1 nH)H^3/2

(b) With the velocity of approach is taken into account,

water surface above the crest of weir, and n is the number of end contractions.

Percentage error discharge over a 



Similarly percentage error in discharge in a rectangular weir