Bernoulli's Principle

2.6

Bernoulli's Principle

	Bernoulli's principle
	In a steady flow of a fluid, fluid pressure decreases as fluid velocity increases and vice versa.

Application of Bernoulli's principle

Insecticide sprayers
- The piston is pushed in, high air velocity on nozzle
- The air pressure in the nozzle is lower than atmospheric pressure
- Atmospheric pressure acts on the surface of the insecticide
- Insecticide moves up through the tube
Bunsen burner
- Gas flowing at high velocity, resulting in a lower pressure inside than atmospheric pressure
- Air from outside is drawn in, mixed with gas
- Gas and air mixture enables the burning of gas
Plane wing (aerofoil)
- Air moves at higher velocity over the wing, resulting in lower pressure
- Air moves slower under the wings, resulting in a higher pressure
- Pressure below wing is higher than the pressure at the top
- Resultant force acting upwards (lift)
Car spoiler ( inverted aerofoil)
- Air moves at lower velocity over the wing, resulting in higher pressure
- Air moves faster under the wings, resulting in a lower pressure
- Pressure below wing is lower than the pressure at the top
- Resultant force acting downwards

2.6

Bernoulli's Principle

	Bernoulli's principle
	In a steady flow of a fluid, fluid pressure decreases as fluid velocity increases and vice versa.

Application of Bernoulli's principle

Insecticide sprayers
- The piston is pushed in, high air velocity on nozzle
- The air pressure in the nozzle is lower than atmospheric pressure
- Atmospheric pressure acts on the surface of the insecticide
- Insecticide moves up through the tube
Bunsen burner
- Gas flowing at high velocity, resulting in a lower pressure inside than atmospheric pressure
- Air from outside is drawn in, mixed with gas
- Gas and air mixture enables the burning of gas
Plane wing (aerofoil)
- Air moves at higher velocity over the wing, resulting in lower pressure
- Air moves slower under the wings, resulting in a higher pressure
- Pressure below wing is higher than the pressure at the top
- Resultant force acting upwards (lift)
Car spoiler ( inverted aerofoil)
- Air moves at lower velocity over the wing, resulting in higher pressure
- Air moves faster under the wings, resulting in a lower pressure
- Pressure below wing is lower than the pressure at the top
- Resultant force acting downwards