Geometry of intensive scalar dissipation events in turbulence

Abstract

Maxima of the scalar dissipation rate in turbulence appear in form of sheets and correspond to the potentially most intensive scalar mixing events. Their cross-section extension determines a locally varying diffusion scale of the mixing process and extends the classical Batchelor picture of one mean diffusion scale. The distribution of the local diffusion scales is analysed for different Reynolds and Schmidt numbers with a fast multiscale technique applied to very high-resolution simulation data. The scales take always values across the whole Batchelor range and beyond. Furthermore, their distribution is traced back to the distribution of the contractive short-time Lyapunov exponent of the flow.

arXiv comment4 pages, 5 Postscript figures (2 with reduced quality)

References in corpus (5)

• Universal long-time properties of Lagrangian statistics in the Batchelor regime and their application to the passive scalar problem
• Very fine structures in scalar mixing
• A Bound on Mixing Efficiency for the Advection-Diffusion Equation
• Multiscale Mixing Efficiencies for Steady Sources
• Geometric features of the mixing of passive scalars at high Schmidt numbers

Cited by in corpus (6)

• Fine-scale statistics of temperature and its derivatives in convective turbulence
• Sub-Kolmogorov-Scale Fluctuations in Fluid Turbulence
• Fractal iso-level sets in high-Reynolds-number scalar turbulence
• Extreme dissipation event due to plume collision in a turbulent convection cell
• Dissipation Scale Fluctuations and Chemical Reaction Rates in Turbulent Flows
• Connecting finite-time Lyapunov exponents with supersaturation and droplet dynamics in the bulk of a turbulent cloud