Tuesday, August 28, 2012

1208.5204 (Andrew W. Baggaley et al.)

Three-dimensional inverse energy cascade induced by vortex reconnections    [PDF]

Andrew W. Baggaley, Carlo F. Barenghi, Yuri A. Sergeev
A recent study of homogeneous isotropic turbulence by Biferale, Musacchio and Toschi has determined that a three-dimensional inverse energy cascade is possible if the nonlinearity of the Navier-Stokes equation is restricted in Fourier space to helical modes of the same sign. In low-temperature superfluid helium, viscosity is zero, vorticity takes the form of discrete, thin vortex filaments of fixed circulation, and turbulence is a tangle of such filaments. We exploit the simpler nature of quantum vorticity to show that the three-dimensional inverse energy cascade can arise from reconnections of vortex loops of the same polarity which shift energy from small length scales to large length scales, in analogy to what was envisaged by Biferale and collaborators in classical Navier-Stokes turbulence. We discuss superfluid turbulence experiments and the observed generation of the classical Kolmogorov energy spectrum in view of this finding.
View original: http://arxiv.org/abs/1208.5204

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