How do we calculate Loss of Head due to Friction in Pipe? What is the major cause of loss of head or energy in a pipe?

According to Darcy’s formula, the loss of head due to friction in the pipe (hf) is given by

where

f = Darcy’s coefficient,

l = Length of pipe,

v = Mean velocity of liquid in pipe, and

d = Diameter of pipe.

The major loss of head or energy is due to friction. The minor loss of head includes the following cases:

(a) Loss of head due to sudden enlargement,

(b) Loss of head due to sudden contraction,

where

Cc= Coefficient of contraction.

(c) Loss of head at the inlet of a pipe,

(d) Loss of head at the outlet of a pipe,