The Coanda Effect

By Jean-Louis Naudin
created on September 26th, 1999 - JLN Labs - Last update September 27th, 1999

The Coanda Effect has been discovered in1930 by the Romanian aerodynamicist Henri-Marie Coanda (1885-1972). He has observed that a steam of air (or a other fluid) emerging from a nozzle tends to follow a nearby curved surface, if the curvature of the surface or angle the surface makes with the stream is not too sharp.

If a stream of water is flowing along a solid surface which is curved slightly from the stream, the water will tend to follow the surface.

Now, a very simple demonstration :

• If you approach gently a curved shaped surface (like the shape of the primary hull of the Repulsin) under a stream of water (see below ) :

• The water follows the surface of the curved shape, this is the Coanda Effect (see below) :

The Coanda Effect works with any of our usual fluids, such as air at usual temperature, pressures and speeds.

See also : THE COANDA FLYING SAUCER TESTS

You may see also the video of the Coanda Effect in action with a water stream :

RealVideo of the Coanda Effect in action (48kb)

( if you don't have the RealPlayer 5.0, you may download it freely at : http://www.real.com/products/player/ )

See also ; THE COANDA FLYING SAUCER TESTS ( Repulsin type A )

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