Knotted Vortices Unravel Truths for Physicists
A knotted vortex created in water.
CREDIT: Robert Kozloff/University of Chicago
Researchers have successfully created a knotted water vortex, a feat akin to tying a smoke ring into a knot. The achievement allows scientists to study this previously unobserved phenomena in a laboratory.
Dustin Kleckner, a postdoctoral scientist at the University of Chicago’s James Franck Institute, is one of the scientists behind the creation of the knotted vortices. He said the unexpected thing about vortex loops is that they break apart by stretching themselves.
The vortex knots actually elongate themselves while circulating in opposite directions. They then move toward each other, eventually colliding and unknotting themselves. This process has previously gone unstudied because researchers have never before been able to create knotted vortices so clearly.
But using wing-shaped “hydrofoils” created using a 3D printer, Kleckner and William Irvine, assistant professor in physics at the University of Chicago, were able to create vortex loops underwater. The scientists coated the hydrofoils with hydrogen and oxygen bubbles and then accelerated them through water. The bubble-coated loops can be observed using a high-speed camera. The result is something that resembles interconnected smoke bubbles.
The ability to create knotted vortices in the lab can be used to further understanding in many fields of physics, including plasma physics and the study of turbulence, ordinary fluids, and superfluids, scientists say.
For example, physicists in these fields have been conjecturing about the degree of “knottedness” in different systems for nearly 50 years. This new research could help confirm or contradict such conjectures.
“If confirmed, this would deepen our understanding of the dynamics and connections between many disparate physical fields,” Irvine said in a statement. “We don’t know if it’s true or not, but I think we can finally test this in an experiment.”