"Classical" Vortex Nucleation in Superflow Through Small Orifices

TL;DR

This paper uses numerical solutions of the Gross-Pitaevskii equation to study vortex formation in superfluid flow through small orifices, revealing cavitation and vortex detachment at high velocities.

Contribution

It presents the first detailed numerical analysis of vortex nucleation in superflow through small orifices using the Gross-Pitaevskii equation.

Findings

Vortex nucleation occurs above 30% of the speed of sound.

Cavitating bubbles form vortex cores that detach and move downstream.

Flow behavior changes markedly at critical velocity.

Abstract

We report on numerical solutions of the Gross-Pitaevskii equation for two-dimensional flow of a superfluid condensate through a small orifice. Above a critical velocity of about $30\%$ of the speed of sound, cavitation occurs in the throat of the orifice. The cavitating bubbles form the cores of singly quantized vortices which detach from the boundary and are convected downstream.