1/f noise and long-term memory of coherent structures in a turbulent shear flow

Abstract

A shear flow of liquid metal (Galinstan) is driven in an annular channel by counter-rotating traveling magnetic fields imposed at the endcaps. When the traveling velocities are large, the flow is turbulent and its azimuthal component displays random reversals. Power spectra of the velocity field exhibit a $1/f^{\alpha }$ power law on several decades and are related to power-law probability distributions $P(\tau )\sim {\tau }^{-\beta }$ of the waiting times between successive reversals. This $1/f$ type spectrum is observed only when the Reynolds number is large enough. In addition, the exponents $\alpha$ and $\beta$ are controlled by the symmetry of the system : a continuous transition between two different types of Flicker noise is observed as the equatorial symmetry of the flow is broken, in agreement with theoretical predictions.

arXiv comment5 pages, 7 figures

References in corpus (7)

• Soliton Turbulence in Shallow Water Ocean Surface Waves
• Characterizing Quantum-Dot Blinking Using Noise Power Spectra
• Fluctuations of $1/f$ noise and the low frequency cutoff paradox
• Statistical theory of reversals in two-dimensional confined turbulent flows
• Magnetic field reversals and long-time memory in conducting flows
• Instability in electromagnetically driven flows Part I
• Instability in electromagnetically driven flows Part II

Cited by in corpus (8)

• Convective turbulent viscosity acting on equilibrium tidal flows: new frequency scaling of the effective viscosity
• The low-frequency break observed in the slow solar wind magnetic spectra
• Efficiency of tidal dissipation in slowly rotating fully convective stars or planets
• Variable energy flux in turbulence
• Zonal flow reversals in two-dimensional Rayleigh-Bénard convection
• Long-range correlations with finite-size effects from a superposition of uncorrelated pulses with power-law distributed durations
• Scaling theory for the $1/f$ noise
• Nonaxisymmetric instabilities in turbulent electromagnetic pumps