Question

The height of water on upstream and downstream side of a submerged weir of 4 m length are 23.5 cm and 14 cm. If Cd for free and drowned portions are .61 and .75 respectively, find the discharge over the weir.

(a) m^3/s

(b) 1.35 m^3/s

(c) 3.2 m^3/s

(d) .55 m^3/s

The question was asked by my college director while I was bunking the class.

My doubt stems from Discharge Over different type of weirs topic in division Orifices, Mouthpieces, Notches and Weirs of Fluid Mechanics

Answer 1

Right option is (a) m^3/s

Best explanation: Q = 0.67 * Cd1 * L * √2g * H^1.5 +.  Cd2 * L * h * √2g(H – h)

                        = .67 * .6 * 3 * √2g * (.24 – .13)^1.5  + .8 * 3 * .13 √2g(.24 – .13)

                        = .85 m^3/s.