In practical terms, this finding could help
a submarine and other vessels to virtually double
their speed while moving under the sea, the journal
Physical Review Letters reports.
Swinburne researchers Ivan Vakarelski and Professor
Derek Chan observed that a heated ball can fall
through liquid more than twice as fast as a colder,
'control' ball, according to a Swinburne statement.
The discovery exploits the drag-reducing properties
of a vapour layer formed between a hot body and
surrounding liquid, known as the Leidenfrost effect.
This is a novel application of the familiar phenomenon
where water drops are observed to dance or 'levitate'
around when splashed onto a very hot plate --
known for over 200 years.
"A very hot body - hot enough to vapourise
the thin layer of liquid in contact with it -
can drastically reduce energy-sapping drag forces
when such bodies travel at high speed through
the liquid," Chan said.
(IANS)
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