Characterization of Small-scale Turbulence by Direct Numerical Simulation

Direct Numerical Simulation (DNS) is the numerical solution of the exact three-dimensional, time-dependent Navier-Stokes equations, governing fluid motion. Results from DNS of turbulent homogeneous shear flow provide detailed information on the structure and dynamics of small-scale turbulence.

This image characterizes and depicts small-scale structure in terms of the relative significance of rotational versus straining motion. The red areas correspond to rotation-dominated (high vorticity) regions which concentrate into tube-like structures. The green regions are those with comparable rotation and strain which tend to form sheets and surround the tube-like structures. The blue areas correspond to strain-dominated regions which indicate locally high energy dissipation.

The tubes are oriented at approximately 30-45 degrees from the horizontal: this is the effect of the shear flow.

Credits:

Numerical Simulation

Peter Diamessis (PhD student), Prof. Keiko Nomura
Department of Mechanical and Aerospace Engineering, University of California, San Diego

Visualization

Dr N. Bordes, G. Johnson
San Diego Supercomputer Center, University of California, San Diego

1999-2000