Bernoulli's Principle as Applied to Fluid Flow in Tubes

When a fluid passes through a tube which, narrows or widens along its length, the velocity of the fluid varies. As the tube narrows, the fluid flows faster and, correspondingly, pressure in the narrow section decreases.

As can be seen on the diagram, water is flowing from d1 to d2 to d3.

The water has the highest level at d1 and d3 because the diameter of the tube is narrower at d2. (note that the diameter of d1 = d3). Theoretically, the water level in d3 will be slightly lower than that of d1 because the flow of water won't be as fast as in d1. (remember, the water now is coming form d2) but as for a generalization, I think it is ok to emulate understanding in minds of pupils.

Animation of this can be seen here


The same can be seen if we are using the flow of air.

Where the region of swiftest air flow will have a region of lowest pressure.

1 comment:

Anonymous said...

can u plz explain and compare the speed of fluid flow and its pressure in a uniform tube and a venturi tube