One day, the acoustic tractors will make levitate man
The human levitation is not for tomorrow, but a new breakthrough in this area opens the way to this old fantasy.
British researchers managed to levitate a 16mm diameter polystyrene ball with this technology. A crucial step before making the man avoid him.
Human levitation may not be tomorrow science fiction anymore. British researchers have successfully levitated "large" objects through an acoustic tractor beam, reports Phys.org. A first.
Concretely, an acoustic tractive beam makes it possible to move or to levitate particles thanks to the sound, more exactly thanks to the ultrasonic waves. The principle is the same as with a magnetic tractor beam, except that the acoustic version allows to keep in the air most solid objects, but also liquids, food or even small insects.
Master the rotation
The problem is that so far researchers have come up against a technical limit they thought was insurmountable. As soon as an object exceeded a certain size - around 2 millimeters - the rotation of the sound field ended up being transmitted to the object, making it turn faster and faster and ejecting it from the levitation field.
A solution has just been invented by engineers from the University of Bristol. In their study published in Physical Review Letters on Monday, January 22, they explain that it is possible to control very precisely the speed of rotation of sound field - and thus its stability - by creating some kinds of "sound tornadoes" of which they change periodically the direction of rotation.
Drawing illustration of the different vortices used by Bristol researchers to stabilize their acoustic tractor beam.
By generating short sequences of acoustic vortices rotating in one direction and then in the other, the tractor beam stabilizes, write the scientists. It becomes possible to levitate objects larger than what was thought possible.
The researchers succeeded in levitating a 16-millimeter-diameter ball of polystyrene, the largest object ever "worn" by an acoustic tractor beam. "By using a more powerful device, our simulations suggest that we could be able to levitate objects up to 20 millimeters," they write, adding that these tests were done using 40 kHz ultrasonic waves, a frequency that only bats can hear.
Tomorrow, the levitation of being human?
"For years, acoustics researchers have been frustrated by the size limit," said Asier Marzo, an engineer in the Bristol Department of Mechanical Engineering and lead author of the study, in a statement from the UK University. therefore all the more satisfying. "