1/f noise and long-term memory of coherent structures in a turbulent shear flow
Article dans une revue avec comité de lecture
Date
2019Journal
Physical Review EAbstract
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 α power law on several decades and are related to power-law probability distributions P(τ) ∼ τ−β of the waiting times between succes-sive reversals. This 1/ f type spectrum is observed only when the Reynolds number is large enough. In addition, the exponents α and β 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.
Files in this item
Collections
Related items
Showing items related by title, author, creator and subject.
-
Article dans une revue avec comité de lectureLARABI, Abderrahim; PEREIRA, Michael; RAVELET, Florent; AZZAM, Tarik; OUALLI, Hamid; MENFOUKH, Laiche; BAKIR, Farid (Inderscience Publishers, 2022)The aim of this study is to investigate the influence of disturbed freestream flow by a small cylinder on the laminar separated boundary layer over NACA0012 wing operating at a Reynolds number of Rec = 4.45 × 105. A detailed ...
-
Article dans une revue avec comité de lectureThe advent of the Internet of Things technology has led to a renewed interest in the use of low tip-speed ratio micro-scale wind turbines to supply power to battery-less microsystems. At low tip-speed ratio ( λ), the blade ...
-
Article dans une revue avec comité de lectureWind tunnel experiments provide worthwhile insights for designing efficient micro wind energy harvesters and large-scale wind turbines. As wind tunnel tests with large-scale wind turbines are expensive and not always ...
-
Article dans une revue avec comité de lectureSmall horizontal axis wind turbines operating at low wind speeds face the issue of low performance compared to large wind turbines. A high amount of torque is required to start producing power at low wind speed to overtake ...
-
Article dans une revue avec comité de lectureLAMRI, Abderrahmane; SHIRINBAYAN, Mohammadali; PEREIRA, Michaël; TRUFFAULT, Laurianne; BAKIR, Farid; TCHARKHTCHI, Abbas; FITOUSSI, Joseph (Wiley, 2020)The objective of this work is to initiate the discussion about multiphysics relationships between the molten and solid states of high-density polyethylene (HDPE). The extrusion and the injection processes are employed to ...