This is an open project for students (especially to students of Kendriya Vidyalaya, Pattom Shift 1) to find out an post 101 Applications of Bernoulli's Theorem.
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  • Try to find out more applications of give explanations to already posted applications.
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(1) Atomizer or sprayer
The common form of atomizer is shown in the fig. below
When the rubber bulb is squeezed, the air blows in the tube T with high speed .According to Bernoulli’s theorem a low pressure P2 is created inside T which is much less than atmospheric pressure P1 on the liquid surface in the vessel R. Due to it the liquid rises up in the tube T and is pushed out with air through nozzle N in the form of a spray. This principle is used in a paint sprayer, oil scent and nasal sprayer.
(2) Lift on an aeroplane wing
The shape of the aeroplane wing is peculiar. Its upper surface is
more curved than its lower surface and its leading edge is thicker than its trailing edge. As an aeroplane moves forward, the air blown in the form of stream lines over the wings of aeroplane is shown below.
As the upper surface of wing is more curved than its lower surface, therefore, the speed of air above the wings two is larger than the speed of the air below the wings. According to Bernoulli’s theorem, the pressure above the wings becomes less than that the pressure
below the wings. Due to this difference of pressure on the two sides of the wings, a vertical lift acts on the aeroplane. When this lift is sufficient to overcome the gravity pull on the aeroplane, the aeroplane is lifted up.
(3) Blowing off the roofs during storms
In a storm, the sometimes the light roofs of thatched houses are blown off.
This is because, a high velocity wind blowing over the roofs decreases, the pressure above the roof and therefore the greater atmospheric pressure below the roof lifts it up.
(4) Curved motion of spinning balls
(5) Motion of two parallel boats
(6) Bunsen’s Burner
In Bunsen’s burner, the gas escapes through the fine nozzle N with
a high velocity. It results in lowering of pressure in the neighbourhood of the nozzle. Due to decrease in pressure inside the burner, the atmospheric air enters through the holes HH. The air and the gas mixture rising up produce a flame, when ignited.
(6)A person standing near the railway track is pulled towards the train, when a fast moving train passes closes to him.
The fast train decreases the pressure between the person and the train. Due to the greater pressure on the other side of the person, the person gets pushed towards the railway track.
(7) Two ships sailing in the ocean get pulled towards each other, if they come closer to each other.
(8) Vacuum Brakes
Vacuum Brake is used to stop train in case of emergency.
In order to top train, the steam at pressure decreases and the piston of the brake
gets lifted, which through a mechanical system lifts the brake.


  • Bernoulli's Principle can be used to calculate the lift force on an airfoil if you know the behavior of the fluid flow in the vicinity of the foil. For example, if the air flowing past the top surface of an aircraft wing is moving faster than the air flowing past the bottom surface then Bernoulli's principle implies that the pressure on the surfaces of the wing will be lower above than below. This pressure difference results in an upwards lift force. Whenever the distribution of speed past the top and bottom surfaces of a wing is known, the lift forces can be calculated (to a good approximation) using Bernoulli's equations established by Bernoulli over a century before the first man-made wings were used for the purpose of flight.
  • Bernoulli's principle does not explain why the air flows faster past the top of the wing and slower past the underside. To understand why, it is helpful to understand circulation, the Kutta condition and the Kutta-Joukowski Theorem. The carburetor used in many reciprocating engines contains a venturi to create a region of low pressure to draw fuel into the carburetor and mix it thoroughly with the incoming air. The low pressure in the throat of a venturi can be explained by Bernoulli's principle; in the narrow throat, the air is moving at its fastest speed and therefore it is at its lowest pressure.
  • The Pitot tube and static port on an aircraft are used to determine the air speed of the aircraft. These two devices are connected to the air speed indicator which determines the dynamic pressure of the airflow past the aircraft. Dynamic pressure is the difference between stagnation pressure and static pressure. Bernoulli's principle is used to calibrate the air speed indicator so that it displays the indicated airspeed appropriate to the dynamic pressure.
  • The flow speed of a fluid can be measured using a device such as a Venturi meter or an orifice plate, which can be placed into a pipeline to reduce the diameter of the flow. For a horizontal device, the continuity equation shows that for an incompressible fluid, the reduction in diameter will cause an increase in the fluid flow speed. Subsequently Bernoulli's principle then shows that there must be a decrease in the pressure in the reduced diameter region. This phenomenon is known as the Venturi effect.
  • The maximum possible drain rate for a tank with a hole or tap at the base can be calculated directly from Bernoulli's equation, and is found to be proportional to the square root of the height of the fluid in the tank. This is Torricelli’s law, showing that Torricelli's law is compatible with Bernoulli's principle. Viscosity lowers this drain rate. This is reflected in the discharge coefficient which is a function of the Reynold's number and the shape of the orifice.

  •  In open-channel hydraulics, a detailed analysis of the Bernoulli theorem and its extension were recently developed. It was proved that the depth-averaged specific energy reaches a minimum in converging accelerating free-surface flow over weirs and flumes. Further, in general, a channel control with minimum specific energy in curvilinear flow is not isolated from water waves, as customary state in open-channel hydraulics.
  • The principle also makes it possible for sail-powered craft to travel faster than the wind that propels them (if friction can be sufficiently reduced). If the wind passing in front of the sail is fast enough to experience a significant reduction in pressure, the sail is pulled forward, in addition to being pushed from behind. Although boats in water must contend with the friction of the water along the hull, ice sailing and land sailing vehicles can travel faster than the wind.
  • Textile paper applications
  •  Many explanations for the generation of lift (on airfoils, propeller blades, etc.) can be found; but some of these explanations can be misleading, and some are false. This has been a source of heated discussion over the years. In particular, there has been debate about whether lift is best explained by Bernoulli's principle or Newton’s laws of motion. Modern writings agree that Bernoulli's principle and  Newton's laws are both relevant and correct
             Textile paper applications
            Activated paper chromatography
            The underlying principle of the hydraulic press.
            Used for amplifying the force of the driver's foot in the braking system of most        cars and trucks.
  • Used in artesian wells, water towers, and dams.
  • Scuba drivers must understand this principle. At a depth of 10 meters under water, pressure is twice the atmospheric pressure at sea level, and increases by about 105 kPa for each increase of 10 m depth.

It is an instrument to measure the velocity of flow of a liquid through a pipe line. It is based on Bernoulli’s principle.
Your browser may not support display of this image. It consists of a horizontal tube provided with a constriction. it is connected in series
with the flow pipe. Vertical tubes are connected on the region with lager area and one in region of smaller area.
At the constriction the velocity is increased and consequently pressure is reduced.

It is used for the measurement of rate flow of a liquid. It is based on Bernoulli’s theorem.
Your browser may not support display of this image. It consists of two tubes. the ends of these tubes have smaller aperture and is vertical to the horizontal pipe .
This helps us to determine the rate of flow of the liquid.

1 comment:

harsha said...

the numbering of the apps are not correct and the curved motion of spinning balls can be explained.

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