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."