Australian Researches Develop a Tractor Beam for Water that Can Control the Movement of Drifting Objects

Australian National University researchers have developed a “tractor beam” that could control the movement of a floating particle just by creating a specific pattern of waves.

It is hoped the tractor beam would be developed to assist in cleaning up oil spills and minimize environmental impact. Additionally, it could be used in applications such as retrieving the broken starships or better understanding rip tides, in which swimmers are drawn away from the shore even though the waves are moving towards it.

Physicists create water tractor beam

Dr Horst Punzmann (left) and Professor Michael Shats test their wave-generated tractor beam. Photo by Stuart Hay.

Dr Horst Punzmann and Prof. Micheal Shats are part of the team behind the design.

Using a system of vertically-oscillating plungers, the team was able to generate quasistanding Faraday waves on the surface of the water in order to control the movement of a drifting object. This doesn’t just apply to drawing the object towards the source of the waves; the object can be moved in any direction. The Physicists experimented with a table tennis ball floating in a wave tank.

“We have figured out a way of creating waves that can force a floating object to move against the direction of the wave,” Punzmann said in a press release. “No one could have guessed this result.”

In order to steer the object around in any direction they chose, they were able to control the size and frequency of the waves. Particle trackers revealed that the waves create currents on the surface, based upon the wave’s shape. Plungers of various shapes were used in order to manipulate the pattern of the current’s flow.

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

Despite this, the scientists said that the mathematical theory behind this process is unclear.

Source: Australian National University