Question

Match List - I with List - II and select the correct answer using the codes given below the lists:
List - I
A. Rehbock formula
B. Francis formula
C. A special trapezoidal weir
D. Linear proportional weir

List - II
1. Sutro weir
2. Rectangular suppressed weir
3. Rectangular side-contracted weir
4. Cippolletti weir

Codes:

• A. A B C D
  1 3 4 2
• B. A B C D
  2 4 3 1
• C. A B C D
  1 4 3 2
• D. A B C D
  2 3 4 1

Answer 1

The correct option is D A B C D

2 3 4 1
(i) Rehbock's formula is an empirical formula for calculating discharge in rectangular suppressed weir. It is given by
$Q=\frac{2}{3}(0.605+0.08\frac{H}{Z})+\frac{0.001}{H}\sqrt{2g}L{H}^{\frac{3}{2}}$
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 dischage 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 taken into account

$Q=1.84(L-0.1n{H}_1)(H_1^{3/2}-h_a^{3/2})$

Where $H_1=H+h_a=H+\frac{V_a^2}{2g}$, H is height of water surface above the crest of weir, and n is the number of end contractions.