Coanda effect


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Coanda effect

or

wall-attachment effect,

the tendency of a moving fluid, either liquid or gas, to attach itself to a surface and flow along it. As a fluid moves across a surface a certain amount of friction (called "skin friction") occurs between the fluid and the surface, which tends to slow the moving fluid. This resistance to the flow of the fluid pulls the fluid towards the surface, causing it stick to the surface. Thus, a fluid emerging from a nozzle tends to follow a nearby curved surface—even to the point of bending around corners—if the curvature of the surface or the angle the surface makes with the stream is not too sharp. Discovered in 1930 by Henri Coanda, a Romanian aircraft engineer, the phenomenon has many practical applications in fluidicsfluidics,
branch of engineering and technology concerned with the development of equivalents of various electronic circuits using movements of fluid rather than movements of electric charge.
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 and aerodynamicsaerodynamics,
study of gases in motion. As the principal application of aerodynamics is the design of aircraft, air is the gas with which the science is most concerned. Although aerodynamics is primarily concerned with flight, its principles are also used in designing automobile
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.

Coanda effect

[kō′an·də i′fekt]
(fluid mechanics)
The tendency of a gas or liquid coming out of a jet to travel close to the wall contour even if the wall's direction of curvature is away from the jet's axis; a factor in the operation of a fluidic element.

Coanda effect

Coanda effect
The effect of a jet of air blowing out from an airfoil, or another shape, and reacting with air passing. The air tends to stick to the solid surface even if it curves away, avoiding separation or stall.
References in periodicals archive ?
The jet momentum tended to keep the air jet attached to the ceiling, walls, and floor as a result of the Coanda effect.
The Coanda Effect has been discovered in1930 by the Romanian aerodynamicist Henri-Marie Coanda (1885-1972).
In the region above the backflow, the smoke adheres to the left wall surface, namely the boundary layer attachment or the Coanda effect (Zhuang et al.
Williams is engineering a new noise-attenuating inlet for the nacelle, along with a passive thrust-vectoring system that will use the Coanda effect to deflect thrust 23 deg.
His environmentally friendly design further reduces carbon footprint by channeling engine exhaust along the rotor blades and around the body of the aircraft to provide a cushion of gas for additional lift - an aerodynamic principle known as the Coanda Effect.
It is designed to release a high level of plasmacluster ions at 20 degrees upward angle that is varied along every part of the interior of the car by the Coanda effect.
The supply of inlet jets creates plane jets to both sides of the beam that normally attach to the ceiling, utilizing the Coanda effect.
Results indicate that in the case A the incoming jet remains attached to the ceiling upon entering the room, due to a Coanda effect.
The YC-15 introduced a number of innovative features, such as externally blown flaps, which used double-slotted flaps to direct part of the jet exhaust downwards, while the rest of the exhaust passed through and downward over the flaps, introducing the Coanda effect.
Two-dimensional flow along an inclined plane wall and the impact of Coanda effect on the flow character is described also in the paper of Allery et al.
According to Piper vice-president of engineering, John Becker, engineers are now experimenting using a Coanda effect device that would channel the jet's exhaust in an appropriate direction to reduce nose-down moment created by adding power and nose-up trim changes when decreasing power.
Spray Aiming in Bombardier Beetles: Jet deflection by the Coanda Effect.