Characterization of turbulence in inhomogeneous anisotropic flows

Abstract

We introduce a global quantity $\delta$ that characterizes turbulent fluctuations in inhomogeneous anisotropic flows. This time-dependent quantity is based on spatial averages of global velocity fields rather than classical temporal averages of local velocities. $\delta (t)$ provides a useful quantitative characterization of any turbulent flow through generally only two parameters, its time average $\bar{\delta }$ and its variance ${\delta }_2$. Properties of $\bar{\delta }$ and ${\delta }_2$ are experimentally studied in the typical case of the von Kármán flow and used to characterize the scale by scale energy budget as a function of the forcing mode as well as the transition between two flow topologies.

References in corpus (7)

• Generation of magnetic field by dynamo action in a turbulent flow of liquid sodium
• Magnetic Field Saturation in the Riga Dynamo Experiment
• Multistability and memory effect in a highly turbulent flow: experimental evidence for a global bifurcation
• Towards an experimental von Karman dynamo: numerical studies for an optimized design
• Influence of turbulence on the dynamo threshold
• On the properties of steady states in turbulent axisymmetric flows
• The turbulent dynamo as an instability in a noisy medium