• # What are the most common applications of Bernoulli's principle?

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We live in this world with harmony with nature. Nature always work with laws or principle. It can be laws of thermodynamics or laws of heat transfer or Newton's law of motions or Laws of the planets orbit around the Sun or any law that governs the life on earth. One of them is Bernoulli's principle or the law. What are the most common applications of Bernoulli's principle?

• Bernoulli 's theorem is dependent upon pressure, velocity and elevation in the moving fluid ( liquid or gas) , the compressibility and viscosity though in negligible amount and the flow remaining in the steady state.
To understand the mechanism of Bernoulli's principle let us take the examples of Aircraft and Baseballs explaining its effect -
1) Air flight- The main application of the Bernoulli's theorem is in the architecture of the wings of the plane. The top of the wing is constructed slightly curved where as the bottom one is totally flat. In course of operation in the sky, air travels across both the tops and the bottoms simulteneously. Since both the parts the tops and the bottoms have been designed in the different fashion, this allows for the air on the bottom to move slowly creating more pressure on the bottom and creates a chance for the air to move faster creating less pressure. The resultant effect causes air plane to fly. Air plane is also influenced by a pull of gravity opposing the lift both the drag and the thrust. Thrust is the force enabling the air plane to move forward where as the drag in air resistance opposes the thrust force.
2) Baseball is the ideal example where we can see the application of Bernoulli's principle. Take a close look on the baseball, which appears to curved externally. The entire pitch operates based on Bernoulli's principle. Since the stitches of the ball form a curve, it is essential for the pitches to grip seams of the baseball. The proper gripping allows for the friction to cause a thin layer of air to engulf the misunderstanding of the ball in relation to the bottom of the balls.This causes the bottom part of the ball to accelerate faster in the downward direction as compared to the top part. This phenomenon allows for the ball to curve downward causing the batter to miscalculate the position of the ball.

• Bernoulli's principle is basically an idea of fluid dynamics. This describes that as the speed of the fluid increases, pressure decreases. This principle includes both the work by the pressure and by the changes in potential energy from changes in height.
Below are the common applications of Bernoulli's principle.

1. Airlift:
One of the most common everyday applications of Bernoulli's principle is in airflight. It works in the air flight has to do with the architecture of the wings of the plane. Wings top part is curved and the bottom of the wing is totally flat. Air flows across both the top and the bottom concurrently. This allows for the air on the bottom to move slower, which creates more pressure on the bottom, and allows for the air on the top to move faster, which creates less pressure. Due to which it creates lift, which allows planes to fly.

2. Baseball:
Baseball is a good example you see in everyday life. Baseball is in the shape of a curveball. The ball is spinning in a certain manner, this allows more air pressure on the top of the surface and less air pressure on its bottom surface. Therefore, according to the principle, there should be less speed on the top of the ball than there is on the bottom of the ball, which causes the batter to miscalculate the ball's position.

3. Sailing
This principle also works for creating lift in the sail boats. The sailboats have two parts, a sail which points north and a keel which points in the opposite direction. If the speed of the air increases on the sail then there will be less pressure on the sail and less pressure on the keel, this produces lift and propels the sail to move in the water.

• Bernoulli principle was given by Daniel Bernoulli in his book "Hydrodynamica". According to Bernoulli principle, as the speed of the fluid increases, the pressure in the fluid decreases. The principle is applicable on non compressible, non-viscous and non steady fluid.

Pressure is inversely proportional to the velocity.
Pa1/v
Where P= Pressure
V= Velocity

Faster the speed more kinetic energy is produced. More the pressure, more potential energy s produced.
In a horizontal pipe the highest fluid pressure is in the part where flow speed is the lowest and the lowest pressure is at the part where flow speed is the highest.

Some common applications we can see in the daily life are as follows:
1. Bird flight
In the case of bird flight, in case of faster wind speed, pressure will be low. Air will hit the wings from bottom and wings go up.

2. Hair blower
In a hair blower when internal air pressure increases it accelerates and pushes the air outside the blower where there is atmospheric pressure lower outside the blower as compared to inside. According to theorem a fast moving fluid does not create a lower pressure than some nearby slower air. So high pressure region accelerates air towards any nearby pressure area where pressure is lower. Hence it moves faster into the lower pressure region.

3. Venturi meter
Similarly to the example of hair dryer, fluid flowing into the venture meter of a larger diameter at a higher pressure pushes the fluid into the region of lower pressure of the narrower section of venturi. Here pressure increases in the wide section and pushes the fluid to the narrower region of venture meter out to a lower pressure region.
Similarly "Spaying of liquid from bottle" also works on Bernoulli principle.

4. Heart Attack
Heart attack can also be understood on the basis of Bernoulli principle. Heart attacks occur when plaque is accumulated inside the arteries. This plaque decreases the velocity of blood coming through arteries in turn increase in pressure applied by the heart. As a result of which heart attack occurs.

5.Bunsen burner
Bunsen burner also works on Bernoulli principle. While connecting a Bunsen burner to a gas supply source, gas flows at high velocity and enters into the Bunsen burner through a narrow channel. So it accelerates a low pressure region there. Due to this pressure difference atmospheric air from outside moves in. Hence the combination of air and gas starts gas burning and produce fire.

Other application of Bernoulli principles like Lift of aircraft, Spinning of balls and sailing are already explained in the above posts. Some more applications are like filter pumps; Speed of efflux also works on the same principle.

• Bernoulli's principle deals with the relationship between the speed and pressure of a liquid while flowing. It is quite possible that the liquid might pass from different sized pipes or apertures or other constrictions and accordingly its velocity would decrease or increase. The pressure would also swing in the reverse proportion to this speed of the fluid. There are many applications and presentations of this principle in the real life. Some of them are -

1. Watering the plants - When we water the plants with a pipe connected to a far away tap then we press the end of the pipe by our fingers to constrict the opening and the water starts sprinkling on the plants nicely. This is an example which most of us might be aware and have done so and may not be knowing that we were using the Bernoulli's principle. Due to constriction the speed of the water is increases and we can sprinkle it on the plants properly. Otherwise the water would simply fall down just below the end.

2. Attraction between two closely almost parallel moving boats - When two boats move near to each other in the same direction then the water region between them becomes like a constricted space and due to that the pressure there reduces and the water there has slightly more speed than the outside regions and this pressure drop creates an attraction between the boats.

3. Action of a sprayer - There are many spray applications where a liquid is sprayed with the help of atomiser or sprayer. This also works based on the Bernoulli's principle. When we push air by pressing the knob on the sprayer or bulb on an atomiser then due to the high speed of air there, the pressure in that region drops and the liquid comes up from the spray bottle through the vertical tube and tries to escape in the direction of the air movement making a spray or mist.

4. Dynamic lift on an Aeroplane - The wings of the Aeroplanes are designed in such a way that there is difference of air speed above and below and that creates a pressure difference which is utilised for uplifting the Aeroplane. Once this pressure difference is sufficient then the plane would lift up due to enormous upward force on the wings.

5. Movement of a spinning ball - When a ball is thrown with spinning it takes a curvature path due to the difference of pressure along its side. This is understood and utilised by the tennis players while spinning and striking the ball in a particular manner.

6. Gas burner - In any gas burner the gas is taken from a small aperture and it moves with good speed and due to the pressure drop the surrounding air gushes to it and adds to it for proper burning. In earlier kerosine stoves same principle was used. The heated kerosine moved through a small hole and burns above it comfortably taking the oxygen from the surroundings.

7. Blowing of roof of house during storms or high speed winds - Sometimes due to high speed wind the pressure above the roof decreases sharply and this gives a upthrust on the roof from the inside of the house and if the roof is not fastened properly it could blow away.

8. Speed of ship near port or shallow water - In shallow waters the captain of the ship takes care as not to move the ship with more speed as that could make the pressure in the bottom constricted part lower and there would be drag on ship downwards making it vulnerable for striking with the sea bed.

Knowledge is power.