Question

Gibb’s module holds good for the standard design in which _________

(a) Outlet index m = 2 and H/D = 1/7

(b) Outlet index m = 1/3 and H/D = 1/7

(c) Outlet index m = 5/3 and H/D = 1/7

(d) Outlet index m = 2/3 and H/D = 1/7

This question was addressed to me in an interview for job.

My question is taken from Types of Rigid Modules and Cattle Crossings in chapter Regulation Modules and Canal Structure of Irrigation Engineering

Answer 1

Correct answer is (a) Outlet index m = 2 and H/D = 1/7

Easy explanation: It is a modular outlet with costly and complicated arrangements. It is based on the free vortex flow and holds good for the standard design in which outlet index = 2 and H/D = 1/7 where H is the head at the outer circumference and D is the difference of the level measured from the minimum water level in the parent channel to the floor of eddy chamber.