New research on turbulence from The Australian National University will enhance wind energy technologies and improve predictions on cyclone behaviour.
The findings, published today by Dr Hua Xia, David Byrne and Professor Michael Shats from ANU, with colleague Professor Gregory Falkovich from the Weizmann Institute of Science in Israel, have the potential to address one of the most important questions in meteorology: how to better predict the behaviour of tropical cyclones.
‘Tropical cyclones, which can be up to 1000 kilometres in diameter, are dampened by their drag over ocean and land,’ said Professor Shats. ‘This drag was expected to increase with wind speed. However, meteorologists find quite the opposite ’ the stronger the cyclone the lower the drag.
?Our research shows that as a vortex, or a whirling masse of fluid, moves, it modifies turbulence beneath it. This reduces its drag as well as changes the turbulence so that it feeds a large vortex rather than dampening it.
‘In other words, cyclones lose less momentum and energy the stronger they get,’ he said.
Professor Shats said that laboratory experiments revealed that large vortices have the capacity to transform a three-dimensional turbulent flow into a two-dimensional flow.
‘Three-dimensional turbulence ’ in which vortices stretch vertically - are observed universally, and can be seen in things like water flowing through a pipe,? said Professor Shats.