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Water tractor beam: Complex waves generate flow patterns to manipulate floating objects

Date:
August 10, 2014
Source:
Australian National University
Summary:
Physicists have created a tractor beam on water, providing a radical new technique that could confine oil spills, manipulate floating objects or explain rips at the beach.
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Dr. Horst Punzmann and professor Michael Shats demonstrate their water tractor beam.
Credit: Stuart Hay, ANU

Physicists at The Australian National University (ANU) have created a tractor beam on water, providing a radical new technique that could confine oil spills, manipulate floating objects or explain rips at the beach.

The group, led by Professor Michael Shats discovered they can control water flow patterns with simple wave generators, enabling them to move floating objects at will.

"We have figured out a way of creating waves that can force a floating object to move against the direction of the wave," said Dr Horst Punzmann, from the Research School of Physics and Engineering, who led the project.

"No one could have guessed this result," he said.

The new technique gives scientists a way of controlling things adrift on water in a way they have never had before, resembling sci-fi tractor beams that draw in objects.

Using a ping-pong ball in a wave tank, the group worked out the size and frequency of the waves required to move the ball in whichever direction they want.

Advanced particle tracking tools, developed by team members Dr Nicolas Francois and Dr Hua Xia, revealed that the waves generate currents on the surface of the water.

"We found that above a certain height, these complex three-dimensional waves generate flow patterns on the surface of the water," Professor Shats said. "The tractor beam is just one of the patterns, they can be inward flows, outward flows or vortices."

The team also experimented with different shaped plungers to generate different swirling flow patterns.

As yet no mathematical theory can explain these experiments, Dr Punzmann said.

"It's one of the great unresolved problems, yet anyone in the bathtub can reproduce it. We were very surprised no one had described it before."


Story Source:

The above post is reprinted from materials provided by Australian National University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Horst Punzmann, Nicolas Francois, Hua Xia, Gregory Falkovich, Michael Shats. Generation and reversal of surface flows by propagating waves. Nature Physics, 2014; DOI: 10.1038/nphys3041

Cite This Page:

Australian National University. "Water tractor beam: Complex waves generate flow patterns to manipulate floating objects." ScienceDaily. ScienceDaily, 10 August 2014. <www.sciencedaily.com/releases/2014/08/140810214202.htm>.
Australian National University. (2014, August 10). Water tractor beam: Complex waves generate flow patterns to manipulate floating objects. ScienceDaily. Retrieved July 29, 2015 from www.sciencedaily.com/releases/2014/08/140810214202.htm
Australian National University. "Water tractor beam: Complex waves generate flow patterns to manipulate floating objects." ScienceDaily. www.sciencedaily.com/releases/2014/08/140810214202.htm (accessed July 29, 2015).

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