Why the pressure reduces when diameter of pipe is reduced?

Where the water pipe diameter reduces, the velocity of water increases and the water pressure drops - in that section of the pipe.




The narrower the pipe, the higher the velocity and the greater the pressure drop. If the velocity is zero, the pressure drop is zero. If the velocity is very high, the pressure drop too is very high. By pressure, it is understood as the force acting on the walls of the pipe.
Area of cross-section of the flow is inversely proportional to velocity of flow.

Area ∝ (1/velocity)

AV= constant.

A1V1=A2V2

Here

As the area of cross-section decreases velocity increases .

But pressure decrease will easily be explained with the help of Bernoulli's equation



As the pressure decreases in the nozzle with increase in the velocity because they both are inversely proportional.their relation can be deduced by the Bernoulli's equation.

Here sum of pressure and kinetic energies is constant,so as the pressure energy decreases kinetic energy should increase to keep the sum the kinetic energy increases velocity increases.





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