Identifying a superfluid Reynolds number via dynamical similarity

Abstract

The Reynolds number provides a characterization of the transition to turbulent flow, with wide application in classical fluid dynamics. Identifying such a parameter in superfluid systems is challenging due to their fundamentally inviscid nature. Performing a systematic study of superfluid cylinder wakes in two dimensions, we observe dynamical similarity of the frequency of vortex shedding by a cylindrical obstacle. The universality of the turbulent wake dynamics is revealed by expressing shedding frequencies in terms of an appropriately defined superfluid Reynolds number, ${\mathrm{Re}}_s$, that accounts for the breakdown of superfluid flow through quantum vortex shedding. For large obstacles, the dimensionless shedding frequency exhibits a universal form that is well-fitted by a classical empirical relation. In this regime the transition to turbulence occurs at ${\mathrm{Re}}_s\approx 0.7$, irrespective of obstacle width.

5 pages,3 figures

References in corpus (5)

• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Dynamics and statistical mechanics of ultra-cold Bose gases using c-field techniques
• Characterization of reconnecting vortices in superfluid helium
• Inverse Energy Cascade in Forced 2D Quantum Turbulence
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Cited by in corpus (5)

• Observation of von Kármán Vortex Street in an Atomic Superfluid Gas
• Moving obstacle potential in a spin-orbit-coupled Bose-Einstein condensate
• Quantum turbulence in Bose-Einstein condensates: present status and new challenges ahead
• The onset of nanoscale dissipation in superfluid He-4 at zero temperature: the role of vortex shedding and cavitation
• Proper Orthogonal Decomposition of a Superfluid Turbulent Wake