BERNOULLI'S PRINCIPLE

What is that?

• It explains why and airplane gets lift

• It explains why a curve ball curves

• It can impress your friends

Theory of Flight Aerodynamics

• Bernoulli principle “As the air velocity increases, the pressure

decreases; and as the velocity decreases, the pressure increases.”

A major part of the knowledge base needed in the design and development of aircraft.

Contributed to the work of G.B. Venturi, an Italian scientist, who first noted the effects of constricted channels on the flow of fluids. A round tube, such as a nozzle or jet engine, designed to increase the speed of flowing gases and liquids is called a venturi.

Why a curve ball curves?

What do the laces do? What does faster/slower rotation do? Demonstrate?

Theory of Flight• The four forces in balance with one

another hold the plane in the air.• The four forces are lift, weight,

thrust, and drag.

Video Demonstration Video Presentation / Bernoulli’s Principle

The Four Forces of Flight• According to the Bernoulli

Principle, there is an increase in the velocity of air as the airflow around an airfoil shape; therefore, there is an increase of the relative wind as it flows above and below the surface of the airplane wing.

The Four Forces of Flight• Lift can be increased in two

ways1. Increasing the forward speed of the airplane. (Increase Relative Wind)2. Increase the angle of attack.

• The pilot can increase the forward speed of the aircraft by applying more power (Thrust).

The Four Forces of Flight• Angle of Attack

The sum of all the tiny forces over the surface of the wing is called the resultant.

The Four Forces of Flight• Angle of Attack

The angle at which lift stops increasing and begins to decrease is called the burble point.

The Four Forces of Flight• Airfoil Shape

It is extremely important to preserve the characteristic curve that the designers built into the airfoil.

Dents, mud, and ice are three common things that can spoil the built-in shape of the airfoil and interfere with the performance of the entire aircraft.

The Four Forces of Flight• Wing Area and Lift

The greater the surface area of the wing, the greater the amount of lift that will be generated.

Gliders and sailplanes are very good examples of how a large wing surface generates lift.

Summary

As air velocity increases, pressure decreases

As velocity decreases, pressure increase Pressure increase creates lift Curveball is a ball adjusting to pressure Bernoulli principle major part of wing

design