Question

Loss of head due to friction is __________

(a) Directly proportional to hydraulic radius

(b) Inversely proportional to velocity

(c) Inversely proportional to hydraulic radius

(d) Directly proportional to gravitational constant

This question was posed to me in my homework.

The doubt is from Loss of Head due to Friction in Viscous Flow in section Viscous Flow & Turbulent Flow of Fluid Mechanics

Answer 1

The correct choice is (c) Inversely proportional to hydraulic radius

The explanation is: Hydraulic radius is one of the properties of a fluid flow in a channel. It controls the water discharge. It also determines the amount of work the channel can do. (Rh=A/P). Thus, it is inversely proportional to loss of head due to friction.