Engineers from the University of Bristol have demonstrated that it’s possible to stably levitate objects using the world’s most powerful acoustic tractor beams. Their findings were published in the Physical Review Letters on Monday.
Acoustic tractor beams use soundwaves to hold particles in the air. It was previously believed they could only be used to levitate very small objects which were about the same size as a wavelength of sound, but the research demonstrates the potential for far larger objects to be levitated.
“Acoustic researchers had been frustrated by the size limit for years, so its satisfying to find a way to overcome it,”said the study’s lead author, Dr Asier Marzo of Bristol’s Department of Mechanical Engineering. “I think it opens the door to many new applications.”
The technique creates a tornado-like effect with acoustic vortices, which researchers said are like, "tornadoes of sound, made of a twister-like structure with loud sound surrounding a silent core."