Thesis

Energy spectra of interacting Schrödinger-vortex configurations

Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2024
Thesis identifier
  • T17172
Person Identifier (Local)
  • 202053656
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • By means of parallel numerical computations, I investigate the energy spectra of Kelvin wave cascade and fully developed turbulence in Schrödinger fluids. I examine the generation and dynamics of Kelvin waves generated by a single reconnection and the associated cascade of energy to smaller scales. The corresponding energy spectrum of the Kelvin wave cascade is found to have a 𝑘−1 scaling. By following the evolution over large times, I see evidence of statistical equilibration and tendency towards a 𝑘2 spectrum. In the case of fully developed Schrödinger turbulence involving many reconnections and many vortex filaments, I find that the Kelvin wave cascade has a 𝑘−1 spectrum associated with it, although it is observed over a shorter time. Again, letting the tangle evolve over a large time, I see evidence of a tendency towards a 𝑘2 spectrum due to energy equilibration through interactions between Kelvin waves. By employing a bundle of quantized vortices as a discrete model of Navier-Stokes vortices, I investigate the physics of vortex stretching in classical turbulence. Two configurations were attempted: a Hopf link, where I found that the counter-rotating bundles develop a sinusoidal instability that generates tight secondary structures; the corresponding energy spectra of these secondary structures shows a 𝑘−5⁄3 scaling. I also tried a vortex collider configuration where it was found that due to self-stretching and without any reconnections, the energy spectra shows a 𝑘−5⁄3 scaling.
Advisor / supervisor
  • Kivotides, Demosthenes
Resource Type
DOI

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