Question

Water is flowing through a horizontal pipe in a streamline flow. At the narrowest part of the pipe ______.

Options

• velocity is maximum and pressure is minimum.

• pressure is maximum and velocity is minimum.

• both the pressure and velocity are minimum.

• both the pressure and velocity are maximum.

Answer 1

Water is flowing through a horizontal pipe in a streamline flow. At the narrowest part of the pipe velocity is maximum and pressure is minimum.

Explanation:

Using the equation of continuity,

A₁v₁ = A₂v₂ 

In streamlined flow, as the product of Av is a constant, the velocity at the narrowest part will be maximum.

By using Bernoulli’s principle,

`P + 1/2 rho v^2 rho g h` = constant

Here, ρgh is constant because the pipe is horizontal.

As velocity increases, for the equation to remain constant, P has to decrease.

∴ Velocity will be maximum and pressure is minimum.