http://antidepressionguide.org depression symptoms - depression treatment - depression help - Depression Causes, Symptoms, Types, Signs, Facts, Medication Wed, 08 Feb 2012 22:31:05 +0000 en hourly 1 http://wordpress.org/?v=3.0.2 http://antidepressionguide.org/2008/07/04/jet-engine-silencer/ http://antidepressionguide.org/2008/07/04/jet-engine-silencer/#comments Fri, 04 Jul 2008 14:07:00 +0000 Tom
Now, though, Dimitri Papamoschou at the University of California, Irvine, US, says it is possible to quieten a jet engine by separating its exhaust into high and low speed flows.

He says that most of an engine's noise comes from turbulence in the fastest-flowing air. By separating the air into two channels of different speeds, he says the noise can be directed upwards, away from the ground and its inhabitants.

In simulations, funded by NASA, Papamoschou found that this technique can reduce the amount of noise heading towards the ground by more than 6 decibels.

This is a significant amount given that decibels are a logarithmic scale, so that every drop of 3 decibels is equivalent to a halving of power. A "silenced" engine would produce about a quarter of the acoustic energy of a conventional one and be significantly quieter.

Read the jet-engine silencer patent application.

Justin Mullins, New Scientist consultant]]> http://antidepressionguide.org/2008/07/04/jet-engine-silencer/feed/ 0