Question

The discharge formula used in the design of the syphon well drop is ____________

(a) 8/15 Cd. (2g)^1/2. tan (Q/2). H^5/2

(b) 2/3 Cd. (2g)^1/2. L. H^3/2

(c) 8/15 Cd. (2g)^1/2. tan (Q/2). H^3/2

(d) 2.22H^3/2 [L + 0.4nH]

I had been asked this question during an interview.

Query is from Canal Falls in portion Canal Falls of Irrigation Engineering

Answer 1

Correct choice is (d) 2.22H^3/2 [L + 0.4nH]

The best I can explain: The discharge passing through a trapezoidal notch is given by adding the discharge of a rectangular notch and V-notch which is given by-

Q = 2/3 Cd. (2g)^1/2. L. H^3/2 + 8/15 Cd. (2g)^1/2. tan (Q/2). H^5/2

Q = 2.22H^3/2 [L + 0.4nH]

(Where n = 2 tan (Q/2) and coefficient of discharge = 0.75).