Our paper ‘Universal Drag Law in a Model of Superflow’ has been published in Physical Review Letters!

Our paper ‘Emergent Universal Drag Law in a Model of Superflow’ has been published in Physical Review Letters!

In everyday fluids like air or water, there’s a remarkable principle: if you scale up or down an object -- like increasing a toy airplane intro real one -- the entire flow around it, from the swirling eddies to the resistance it feels, stays the same under the same Reynolds number -- a number indicating how turbulent a flow is. This idea, called dynamical similarity, is why wind tunnels work and why a small model can predict how a full-sized aircraft will fly. It has been a long open question whether this principle applies to superfluids. These exotic quantum liquids can flow without friction and create eddies that behave nothing like those in normal fluids. Does a dynamical similarity exist when the rules of viscosity break down? In this study, researchers answered this long open question by simulating the behaviour of drag generated in a superfluid wind tunnel found a clear answer: yes. When the superfluid flow becomes turbulent -- sprouting quantized vortices -- the drag on an obstacle follows the same universal pattern seen in classical fluids. Counterintuitively, they find that streamlined obstacles, such as airplane wings, generate much more turbulence in a superfluid than they would in everyday fluids and propose a practical method to measure this drag in experiments. By showing this connection, the work offers a new approach to using superfluids as a testbed for studying aspects of turbulence, an area of classical physics that to this day is not fully understood.

You can find the full text here!