| Theme | Fluid Mechanics |
| Category | Physics Experiments |
| Short description | This experiment is carried out at the Alcobendas Science Museum, in one of the experiments in the interactive area. It explains one of the reasons why aircraft flythe elevation of the wings according to the Bernoulli principle. In the video you can see how the wing is lifted just by the action of the wind and its own geometry. |
STEP-BY-STEP EXPERIMENT ON WHY AEROPLANES FLY. BERNOULLI.
This experiment is carried out in the Alcobendas Science Museumwhere they have an interactive area full of very interesting physics experiments.
- It consists of a wing profile (wing section as if you cut it in half) and an air fan. When you turn on the button the air starts to come out and you can see how the wing rises, just by the action of its geometry.
2. At the beginning of the experiment the wing section is at rest.
3. As the air begins to exit the wing section rises, purely by the action of its geometry and the wind. This would simulate the action of a moving aircraft and the air from the fan would be the wind itself, which would collide head-on with the moving aircraft.
Bernoulli Aircraft Experiment. Step 3
This wing lift is due to the Bernoulli principle (explained in the next section), whereby the air over the top of the wing exerts less pressure than the air over the bottom of the wing. As there is more pressure below than above, wing lift is produced.
The Bernoulli principle and wing geometry is not the only reason why aircraft fly.
TECHNICAL EXPLANATION EXPERIMENT
What happens is that air travelling over the top of the wing travels faster than over the bottom of the wing. This is in order to fulfil the principle of conservation of massThe air flow in must be equal to the air flow out. As it has to cover more distance over the top, it has to cover it faster.
The Bernoulli principle on the other hand tells us that the energy in closed flow streams remains constant in each section. The energy of the flow is due to its velocity (kinetic), its height (potential) and its pressure. If the velocity of the flow varies, in order to keep the energy constant, its pressure must decrease (taking into account that the head does not vary). The pressure at the top of the wing is therefore lower than at the bottom, which causes the wing to sustain itself.
This last effect of suction due to increased speed is known as the venturi effect.
FURTHER APPLICATIONS OF THE BERNOULLI PRINCIPLE
Bernoulli's principle is the principle by which a sailing boat can sail against the wind.
In the case of a Formula 1 car, it has spoilers that have an inverse geometry to the wings of an aeroplane to keep the ground glued to the tarmac so that it doesn't fly away.