Name: bernoulli's principle in fluid devices
Uploaded: 2023-05-16T08:18:41.000Z
Duration: 1 min 17 s
Channel: JoVE

Bernoulli&#39;s principle has several practical applications, such as Bunsen burners, perfume bottles, and fire hose nozzles.
A venturi tube is one such application, used to measure the velocity of a fluid flowing in a pipe.
It consists of a converging part, the throat, and a diverging part.
Two thin vertical tubes are connected to a venturi tube&#8212;one before the converging part and one at the throat region.
Its working is based on the continuity equation and Bernoulli&#39;s principle.
According to the continuity equation, if the pipe&#39;s cross-sectional area decreases, the velocity of the flow must increase.
According to Bernoulli&#39;s principle, the increase in flow velocity is accompanied by a decrease in pressure.
So, the pressure near the inlet is high, and the pressure at the center of the throat region is low. The height difference in the level of fluid in the vertical tubes is the measure of pressure difference.
If the cross-sectional areas are known, one can solve these equations to obtain the velocity of the fluid flowing through the tube.

principe van bernoulli: toepassingen

Er zijn veel apparaten en situaties waarin vloeistof op een constante hoogte stroomt en dus kan worden geanalyseerd met behulp van het principe van Bernoulli. Deze apparaten omvatten, maar zijn niet beperkt tot, meesleepapparatuur en apparatuur voor het meten van de vloeistofstroom. Meevoerapparaten gebruiken een hoge vloeistofsnelheid om lage druk te creëren en zo de ene vloeistof in de andere mee te nemen. Hieronder vindt u enkele voorbeelden van deze apparaten: <ol> <li>Een bunsenbrander gebruikt een verstelbaar gasmondstuk om lucht mee te voeren voor een goede verbranding.</li> <li>Een verstuiver gebruikt een knijpbol om een luchtstraal te creëren die parfumdruppels meevoert.</li> <li>Verfspuiten en carburateurs gebruiken zeer vergelijkbare technieken om hun respectievelijke vloeistoffen te verplaatsen.</li> <li>Een gewone aspirator gebruikt een snelle waterstroom om een gebied met lagere druk te creëren. Aspirators kunnen worden gebruikt als zuigpompen in tandheelkundige en chirurgische situaties, voor het leegpompen van een ondergelopen kelder of voor het verminderen van de druk in een vat.</li> <li>De schoorsteen van een waterverwarmer is ontworpen om lucht mee te voeren in de buis die door het plafond loopt.</li> </ol> Sommige apparaten gebruiken het principe van Bernoulli voor het meten van de vloeistofsnelheid. Voorbeelden van deze apparaten zijn Prandtl-buizen, ook bekend als pitotbuizen, Venturi-buizen en een manometer die is aangesloten op twee buizen die dicht bij elkaar liggen en klein genoeg zijn om de stroom niet te verstoren.

Principe van Bernoulli: toepassingen

There are many devices and situations in which fluid flows at a constant height and so can be analyzed using Bernoulli&#39;s principle. These devices ...

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Education

JoVE Core

Physics

Natuurkunde

Unit 1

Onderdeel 1

Fluid Mechanics

Stromingsleer

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

Bernoulli's Principle: Applications

bernoulli's principle in fluid devices

Bernoulli's principle helps explain how many fluid devices work when the fluid moves at a constant height. It is useful for devices that use fast flow to create low pressure and for devices that measure fluid speed.

Some devices use this pressure change to pull one fluid into another. These are called entrainment devices. A Bunsen burner uses an adjustable gas nozzle to entrain air for proper combustion. An atomizer uses a squeeze bulb to make a jet of air that pulls perfume drops into the flow. Paint sprayers and carburetors work in a very similar way to move their liquids.

Other examples include a common aspirator, which uses a high-speed stream of water to create a lower-pressure region. Aspirators can act as suction pumps in dental and surgical settings. They can also help drain a flooded basement or reduce the pressure in a vessel. A water heater chimney is also designed to entrain air into the pipe leading through the ceiling.

Bernoulli's principle is also used to measure fluid speed. Prandtl tubes, also called pitot tubes, Venturi tubes, and a manometer connected to two close tubes can all be used for this purpose. The tubes must be close together and small enough not to disturb the flow.

Bernoulli's Principle in Fluid Devices

characteristics of fluids

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Fluid behavior under force differs from the behavior of solids. When a force acts parallel to the top surface of a solid, the solid resists it because of internal friction between its layers. This is called shearing resistance. If the force is removed, the shearing forces help the solid return to its original shape. Other deformation forces can also change the shape of a solid for a short time, as long as the force stays below a threshold magnitude. Solids usually keep their shape, which makes...

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density

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Density helps explain why objects sink or float in a fluid. It is also useful for identifying a substance and for learning about its phase and substructure. The SI unit of density is kg/m3, and the cgs unit is g/cm3. Liquids and solids usually have densities that are roughly comparable. That matches the fact that their atoms are in close contact. Gases have much lower densities than liquids and solids because their atoms are separated by large amounts of empty space. Density does not always...

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Atmospheric pressure and altitude are closely linked. As height increases, atmospheric pressure decreases. This happens because the gravitational force per unit area becomes smaller as we move away from Earth’s surface. To describe this change, the atmosphere is treated with a constant air temperature at a given altitude. The ideal gas law of thermodynamics is also used as a good approximation for the air. Let p(y) be the atmospheric pressure at height y. The density ρ at y, the temperature T...

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pascal's law

Pascal’s Principle in Static Fluids

Pascal’s principle explains how pressure changes move through a fluid that is not flowing. A fluid at rest is in static equilibrium. If the fluid is water, it is in hydrostatic equilibrium. In this state, the net force on any part of the fluid must be zero, or the fluid will begin to flow. Blaise Pascal described this idea in 1653 in Treatise on the Equilibrium of Liquids. He showed that when pressure changes in an enclosed fluid, that change is transmitted without loss through the fluid and...

application of pascal's law

Hydraulic Force Transfer with Pascal's Law

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pressure gauges

Gauge vs Absolute Pressure

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archimedes' principle

Buoyant Force from Fluid Pressure

Archimedes' principle explains buoyant force in a fluid. An upward buoyant force acts on an object that is partially or fully immersed in a fluid. This force is equal to the weight of the fluid displaced by the object. To see why an object floats, imagine removing a submerged object from the fluid. The space it occupied would be filled by fluid with weight w_fl. That weight is supported by the surrounding fluid, so the buoyant force must match the weight of the displaced fluid. The principle...

density and archimedes' principle

How Buoyancy Depends on Density

Buoyancy and density explain why some objects float and others sink. A lump of clay sinks in water, but the same clay can float when it is shaped like a boat. The change in shape lets it displace more water, which increases the buoyant force even though its mass stays the same. The same idea applies to steel ships. An object with an average density lower than the surrounding fluid will float. The fluid has more mass in the same volume, so it has more weight. The buoyant force equals the weight...

accelerating fluids

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buoyancy

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excess pressure inside a drop and a bubble

excess-pressure-inside-a-drop-and-a-bubble

Surface Tension in Drops and Bubbles

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contact angle

Wetting and Surface Curvature

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rise of liquid in a capillary tube

Capillary Action in Thin Tubes

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laminar and turbulent flow

Fluid Motion Patterns in Air and Water

Fluid dynamics studies fluids in motion. Scientists often use velocity vectors to show fluid motion in places like meteorology. For example, wind in the atmosphere can be mapped with vectors that show the speed and direction of the wind at each point. Another way to show fluid motion is with a streamline. A streamline shows the path of a small volume of fluid as it flows. When the flow changes with time, the streamlines do not match the flow lines. The fluid velocity is always tangential to...

equation of continuity

Fluid Flow in Narrowing Pipes

Fluid flow in a pipe is described by flow rate and average speed. Flow rate, or volume flow rate, is the amount of fluid that passes a point through an area in a given time. It depends on both how fast the fluid moves and the size and shape of the conduit. For a river or pipe, a greater speed usually means a greater flow rate. A larger cross-sectional area also increases flow rate. That is why the same fluid can move differently through conduits of different sizes. The relationship becomes...

bernoulli's equation

Fluid Pressure and Speed in Motion

Bernoulli's equation connects fluid pressure with fluid speed. It helps explain why moving fluids can create pressure changes in everyday situations. One example is when two trains pass each other quickly and seem to pull inward. The same effect can happen when two cars pass each other at high speed. As the air between the trains or cars speeds up, its pressure drops. The air on the outside stays at atmospheric pressure. That pressure difference creates a net inward force on the vehicles.

bernoulli's principle

Fluid Pressure and Speed Changes

Bernoulli's equation links fluid pressure and fluid speed in a static, incompressible fluid. For horizontal flow, where gravitational energy density stays constant, the equation is especially useful. In that setting, the result is known as Bernoulli's principle. Bernoulli's principle says that fluid pressure drops when speed increases, and pressure rises when speed decreases. This pressure-speed relationship helps explain how moving fluids behave in simple flow situations. It also provides a...

bernoulli's principle: applications

Bernoulli's principle helps explain how many fluid devices work when the fluid moves at a constant height. It is useful for devices that use fast flow to create low pressure and for devices that measure fluid speed. Some devices use this pressure change to pull one fluid into another. These are called entrainment devices. A Bunsen burner uses an adjustable gas nozzle to entrain air for proper combustion. An atomizer uses a squeeze bulb to make a jet of air that pulls perfume drops into the...

energy conservation and bernoulli's equation

energy-conservation-and-bernoulli-s-equation

Bernoulli’s Equation in Streamlined Flow

Bernoulli’s equation describes energy in a moving fluid. It comes from the conservation of energy principle, or the work-energy theorem, applied to an incompressible, inviscid fluid in laminar, steady, irrotational flow. The equation says that pressure energy, potential energy, and kinetic energy per unit volume stay constant along a streamline. Each term has the units of energy per unit volume. The kinetic energy per unit volume is called kinetic energy density, and the potential energy per...

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viscosity

Viscosity and How Fluids Flow

Viscosity describes how easily a fluid flows. Water moves quickly, while honey and maple syrup flow slowly and stick to a surface. That difference comes from fluid friction between liquid layers and between a fluid and the material around it. In this example, water has a lower viscosity than honey and maple syrup. Viscosity is measured in newton-second per meter squared (N·s/m2) or pascal-second (Pa·s). It also changes with temperature and can differ from one fluid to another by several orders...

poiseuille's law and reynolds number

Fluid Resistance, Viscosity, and Flow Regime

Fluid resistance, viscosity, and flow regime shape how liquid moves through a horizontal tube. Fluid flows from high pressure to low pressure. The flow rate, Q, is the ratio of the pressure difference to the resistance in the tube. A larger pressure difference gives a higher flow rate. Poiseuille's law describes laminar flow of an incompressible fluid in a tube. In this relation, the factors that affect flow rate except pressure are grouped into resistance. Resistance depends on the tube size...

stokes' law

Terminal Velocity in a Viscous Fluid

Viscous forces act like friction in a liquid. They resist the relative motion of molecules and pull back on a solid body moving through the fluid. The size of this force depends on the body’s shape and size, its speed, and the liquid’s viscosity, density, and temperature. For a spherical solid object, the force in a fluid is described by Stokes’ law. This law applies only at low Reynolds number, when the flow is laminar and not turbulent. Experiments show that the force is proportional to the...

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key terms and concepts

See how Bernoulli's principle explains entrainment devices and fluid speed tools like Bunsen burners, aspirators, pitot tubes, and Venturi tubes.

Bernoulli's Principle in Fluid Devices | JoVE K12

physics

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Bernoulli's Principle in Fluid Devices

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