Volume 118, Number 1, April 2017
|Number of page(s)||7|
|Section||Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics|
|Published online||09 June 2017|
Detection of vortex coherent structures in superfluid turbulence
1 Institut NEEL, CNRS, Université Grenoble Alpes - F-38042 Grenoble, France
2 SBT/INAC CEA, Université Grenoble Alpes - F-38054 Grenoble, France
Received: 31 March 2017
Accepted: 25 May 2017
Filamentary regions of high vorticity irregularly form and disappear in the turbulent flows of classical fluids. We report an experimental comparative study of these so-called “coherent structures” in a classical vs. quantum fluid, using liquid helium with a superfluid fraction varied from 0% up to 83%. The low-pressure core of the vorticity filaments is detected by pressure probes located on the sidewall of a 78-cm-diameter von Kármán cell driven up to record turbulent intensity . The statistics of occurrence, magnitude and relative distribution of the filaments in a classical fluid are found indistinguishable from their superfluid counterpart, namely the bundles of quantized vortex lines. This suggests that the internal structure of vortex filaments, as well as their dissipative properties have a negligible impact on their macroscopic dynamics, such as lifetime and intermittent properties.
PACS: 47.27.De – Coherent structures / 47.37.+q – Hydrodynamic aspects of superfluidity; quantum fluids / 67.25.dk – Vortices and turbulence
© EPLA, 2017
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