Flow Instabilities in Superfluid Helium due to Oscillating Structures EuHIT Funded Project

Team

David Schmoranzer
Charles University in Prague, Prague, Czech Republic
Andrew J. Woods
Lancaster University, Lancaster, United Kingdom

Overview

Research Infrastructure
Czech Cryogenic Turbulence Facility, Czech Republic
Facilities used
He II Quantum Turbulence (CCTF2)
Project leader
Viktor Tsepelin
Lancaster University, Lancaster, United Kingdom

Abstract

Since its beginnings in the 1950s, the field of quantum turbulence research has been gaining popularity and aiming to complement the studies of classical turbulence. While it requires the use of cryogenic liquids such as the superfluid phase of helium (He II), it brings many new possibilities for research and in the zero temperature limit, it offers a prototype of turbulence simpler than the classical one. Among the many experimental techniques applied to the studies of quantum turbulence in the superfluid phase He II, two in particular have reemerged recently and became of significant interest: i) measurement of damping forces acting on various submerged oscillators; and ii) measurement of vortex line density using second sound attenuation. Both methods have provided valuable insight into the nature of quantum turbulence and its formation/decay and became well-established experimental tools. We propose to finally combine these two techniques in a single experimental setup that would allow measuring the amount of quantized vortices present near an oscillator such as a quartz tuning fork during various stages of the transition to turbulence in He II. In this way, we hope to find the details of the transition to turbulence at various temperatures in the two fluid regime (1 K < T < 2.17 K). Especially, we wish to determine when the first triggering instability occurs in the normal component and when in the superfluid component of He II, as current experimental evidence suggests that a crossover between these two cases may occur at a temperature dependent of the size and frequency of the oscillator.