## Q. 5.1

Water flows through a pipe line of 12 cm diameter under a pressure of 20 N/cm² with average velocity of 4 m/s. Find the total energy in pressure head per unit weight of water at the cross-section which is 10 m above the datum line.

## Verified Solution

The total energy or pressure head of liquid in pipe line by Bernoulli’s equation is:

$H=z+\frac{P}{w}+\frac{V^{2} }{2g}$                    (i)

Substituting the given values of head, depth of flow and velocity head in Eq. (i), we get

$H=10+\frac{20 \times (10)^{4} }{1000 \times 9.81}+\frac{4^{2} }{2 \times 9.81 }$

Therefore,                                H= 31.2 m of water