Energy Spectrum of the 3D Velocity Field, Induced by Vortex Tangle

Abstract

A review of various exactly solvable models on the determination of the energy spectra $E (k) $ of 3D-velocity field, induced by chaotic vortex lines is proposed. This problem is closely related to the sacramental question whether a chaotic set of vortex filaments can mimic the real hydrodynamic turbulence. The quantity $<\mathbf{v(k)v(-k)}>$ can be exactly calculated, provided that we know the probability distribution functional $% \mathcal{P}(\{\mathbf{s}(\xi,t)\})$ of vortex loops configurations. The knowledge of $\mathcal{P}(\{\mathbf{s}(\xi,t)\})$ is identical to the full solution of the problem of quantum turbulence and, in general, $\mathcal{P}$ is unknown. In the paper we discuss several models allowing to evaluate spectra in the explicit form. This cases include standard vortex configurations such as a straight line, vortex array and ring. Independent chaotic loops of various fractal dimension as well as interacting loops in the thermodynamic equilibrium also permit an analytical solution. We also describe the method of an obtaining the 3D velocity spectrum induced by the straight line perturbed with chaotic 1D Kelvin waves on it.