Strongly localized events of energy, dissipation, enstrophy and enstrophy generation in turbulent flows

Abstract

Regions with large fluctuations of energy, rate of energy dissipation, enstrophy and enstrophy generation have been studied experimentally and theoretically. The main objects of this study are the moments of these quantities in turbulent grid flow, circular jet and boundary layer (Tsinober, Kit and Dracos 1992, Kit, Tsinober, and Dracos 1993). Some quantitative aspects of the experimental results are explained by introducing the idea of `local cascades' of helicity, helicity generation and angular momentum.