# Bernoulli's Principal : Behind the Aeroplane Flying

It is discovered by Daniel Bernoulli who was a Swiss Physicist and also a great Mathematician. He is particularly remembered for his Applications of mathematics to mechanics, especially fluid mechanics, and for his pioneering work in probability and statistics. His name is known in the Bernoulli's Principal, a particular example of conservation of energy, which describes the mathematics of mechanism underlying the operation of two important technologies of 20th century: the carburetor and the Airplane wings.

Bernoulli's Principle : He states that " In the streamline flow of an ideal fluid (one which is not viscous), the sum of energy of position(or Potential energy) plus the energy of motion(kinetic energy) plus the pressure energy will remain constant."

i.e. Potential energy + Kinetic energy + Pressure energy = constant

How Lift creates on the wings of airplane ?

Due to its aerofoil shape of the wings, the streamline flow over the top surface of the aerofoil gives a decrease of pressure (increase in velocity). So the total energy is constant and while at the bottom surface there is an increase of pressure with a corresponding decrease in velocity. The decrease in pressure (to that of atmospheric pressure) on the top surface is said to create a partial vacuum, providing a suction effect and the increase of pressure at the bottom  surface provides an upward push on the aerofoil. These effects are increased when the aerofoil is set at a small angle to the airflow which is known as "angle of incidence". These reactions of the airflow provide "Lift and drag" forces.