Sounds of silence

Published: Monday 15 January 1996

Seven researchers working for Mitsubishi in Japan have found a way of making machinery, vehicles and aircrafts operate more silently (New Scientist, Vol 147, No 1997).

When air flows through a pipe, over a wing or into a tunnel, noise is generated. The solution to the problem is to coat any surface in contact with the air with soft fibres. The fibres could be synthetic or natural material, such as animal fur.

The researchers have tested their idea inside a wind tunnel, on the rotor blades of a helicopter and in the pipes of an air conditioner. They have also dressed the overhead power pick-up arms ofa train. In each case, they claim the fur significantly reduced noise.

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