Bernoulli’s effect is an important derivation in mechanics and fluid dynamics. It was first described by the Swiss mathematician Daniel Bernoulli. This is also known as Bernoulli’s principle. He published this theory in 1738 applying mathematical calculus to that science.
According to Bernoulli’s effect in any small volume of space through which a fluid is flowing steadily, the total energy comprising the pressure, gravitational potential and kinetic energy is always constant. In fact, this theory propounds the law of conservation of energy for flowing fluids. It also states, if the velocity of a horizontally flowing liquid or gas increases, its pressure decreases. This effect has many applications in mechanics.
Bernoulli’s effect has helped a great deal in the development of aerodynamics and applied in the design of Airfoil. An aeroplane wing, seen from the tip, is flat at the bottom and curved at the top. As the wing travels through the air, the air must travel either over or under the wing. Air moving over the wing goes a longer distance so it must travel faster. Because the air moving over the wing is travelling faster, there is less air pressure on the top of the wing. This means that there is more pressure on the bottom of the wing, which pushes the wing upward, causing the aeroplane to stay up in the air.
On the basis of this fact, an instrument named Venturimeter was developed by an Italian J.B. Venturi (1746-1822) to measure the velocity of fluids.
A pump is used to spray liquid substances. This is known as an atomizer. The liquid to be sprayed is taken in a container. This container has a tube whose one end has a nozzle and the other end is fitted with a balloon to pump air. A side tube is attached to the middle of this tube which dips into the liquid. When the balloon is pressed the air rushes in through the nozzle with a great speed. This reduces the air pressure in the tube above the liquid. Due to this the liquid rises up and comes out through the nozzle in the form of droplets. A paint sprayer works on the same principle.
The carburettors of cars and buses also operate on the basis of Bernoulli’s effect. Spinning of the cricket ball is also an example of Bernoulli’s effect.
