Vorticity Statistics and the Time Scales of Turbulent Strain

Abstract

Time scales of turbulent strain activity, denoted as the strain persistence times of first and second order, are obtained from time-dependent expectation values and correlation functions of lagrangian rate-of-strain eigenvalues taken in particularly defined statistical ensembles. Taking into account direct numerical simulation data, our approach relies on heuristic closure hypotheses which allow us to establish a connection between the statistics of vorticity and strain. It turns out that softly divergent prefactors correct the usual "1/s" strain time-scale estimate of standard turbulence phenomenology, in a way which is consistent with the phenomenon of vorticity intermittency.

LaTex, 17 pages, 6 figures

References in corpus (5)

• A public turbulence database cluster and applications to study Lagrangian evolution of velocity increments in turbulence
• Efficient numerical diagonalization of hermitian 3x3 matrices
• Lagrangian dynamics and statistical geometric structure of turbulence
• Modeling the pressure Hessian and viscous Laplacian in Turbulence: comparisons with DNS and implications on velocity gradient dynamics
• Local 4/5-Law and Energy Dissipation Anomaly in Turbulence