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 ?
Although superficial similarities might be noted between the surveyed and the present works, the authors know of no literature or working concept to date that specifically exploit the combined mechanisms of the gravitational effects of a rapidly rotating vortex flow on different-density gases and the Coanda effect to achieve the proposed simultaneous charge confinement and stratification in premixed-charge engines.
The tendency of a fluid to stick to smooth surfaces is known as the Coanda effect.
Except for the spray interaction and the Coanda effect, it is the different internal flow characteristics inside the two nozzles that attributes to the deviation between the two kinds of spray properties [14].
Because of the Coanda effect from both the structural floor below and raised floor above, the air would rifle with little induction out to the UFT, providing colder inlet air.
Another option is to use energy efficient nozzles, which reduces air consumption by at least 50%, but uses the coanda effect to entrain the ambient air to increase the overall flow and volume of the air jet.
Since tunnel ventilation systems consume large amounts of energy, with some installations demanding several megawatts at full load, reducing the Coanda effect goes a long way toward improving energy efficiency.
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.
The abstract of a paper published in Environmental Science and Technology reads in part, "Lidar and point sampler measurements show that, as long as the intervention takes place within the zone where the Coanda effect holds the jet to the surface lie.
Thus, the inlets have been located at the ceiling and a Coanda effect was expected.
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.
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.