2008-05-29

Applications of Bernoulli's Principle

1. Aerofoil

The flight of an aeroplane is based on the principle regarding to the effect of the flow of air around its wings, which is, the aerofoil.

An aerofoil shape has a rounded front edge and pointed (sharp) trailing edge. The top surface is arched (curved) and the bottom is flat.

When a wing in the form of aerofoil moves through air, the flow of the air over the top has to travel faster to cover the longer distance (compares to the lower portion) and creates a region of low pressure. The flow of air below the wing is slower resulting in a region of higher pressure.

The difference between the pressures at the top and the bottom creates a NET UPWARD FORCE..(remember! bottom part higher pressure..upper part lower pressure).This is called a Lift and helps the plane to take off.

In addition to that, inverted aerofoils are used in racing cars to create a donward force and stabilize the cars at high speed.

2. Bunsen Burner

When a bunsen burner is connected to a gas supply, the gas flows at high velocity through a narrow passage in the burner, creating a region of low pressure.

The outside air, which is at atmospheric pressure, is drawn in an mixes with the gas.

The mixture of gas and air enables the gas to burn completely to produce a clean, hot fire.

Other applications that you must read on your own.

- Hydrofoil Boat
- Insecticide Spray (or whatever sprays that available)
- The shape of canvas roof ( in car) when its moving - why the roof bulges upward?
- Carburettor
- Curve Ball Spin offs
- The shape of a ski-jumper's body when he's jumping..its curved right? Why?

All the best!!

3 comments:

Anonymous said...

how about Filter pump, Insecticide spray n surfing?

Dean James said...

Insecticide sprayer:

1. When the plunger is pushed in, the air flows at a high velocity through a nozzle (small tube).

2. The flow of air at high velocity creates a region of low pressure just above the metal tube. The higher atmospheric pressure acts on the surface of the liquid insecticide causing it to rise up the metal tube.
(the atmospheric pressure push the insecticide solution upwards to a small tube near the nozzle)

3. The insecticide leaves the top of the metal tube through the nozzle as fine sprays carried by the fast moving air.

(this application is more or same than filter pump)

I am not so sure about surfing though, whether the movement of water below causes any change of pressure but yatch surely uses bernoulli's principle.

WANG'ALIA DONAH said...

CAR ROOF

when one is driving,the air above the car moves at a higher speed than the air inside the car. This causes low pressure above the car roof and a higher pressure in the car which causes the car roof to be pushed upwards.