Question

A rectangular orifice of 2 m width and 1.2 m deep is fitted in one side of large tank. The easier level on one side of the orifice is 3m above the top edge of the orifice while on the other side of the orifice the water level is 0.5 m below it’s top edge. Calculate discharge if       Cd = .64

(a) 4.95 m^3/s

(b) 5.67 m^3/s

(c) 3.56 m^3/s

(d) 6.75 m^3/s

This question was posed to me during a job interview.

This key question is from Flow through Large Orifice topic in section Orifices, Mouthpieces, Notches and Weirs of Fluid Mechanics

Answer 1

Correct choice is (a) 4.95 m^3/s

For explanation I would say: Explanation: Q = Cd * b * (H2 – H) √2gH

                    Here, b = 2

                             H2 = 4.2

                             H = 3.5

                     Q = 4.94 m^3/s.