Diffusion and Dispersion of Passive Tracers in Navier-Stokes and MHD Turbulence
Abstract
The diffusive effects of hydrodynamic and magnetohydrodynamic turbulence are studied from the Lagrangian viewpoint by following tracer particles in high-resolution direct numerical simulations. A comparison of the magnetohydrodynamic with the hydrodynamic case reveals significant differences in the two-particle relative dispersion. Due to the alignment of the Lagrangian tracer velocity with the local magnetic field the relative dispersion is slowed down for τ_d \stackrel{<}{~ } t \stackrel{<}{~} 10 τ_d in the magnetohydrodynamic case, τ_d being the Kolmogorov time. Furthermore the fluid particle trajectories in the vicinity of the smallest dissipative structures are found to be characteristically different.
}wcm- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMSH13A0390B
- Keywords:
-
- 4400 NONLINEAR GEOPHYSICS (3200;
- 6944;
- 7839);
- 4430 Complex systems;
- 4475 Scaling: spatial and temporal (1872;
- 3270;
- 4277);
- 4499 General or miscellaneous