Turbulence Structure Associated with Intercomponent and Interscale Energy Transfer and Modification by Forcing
Abstract
There are two parts to this research program. First program focusses on the quantification of loosely held concepts such as 'structure,' and 'dynamic significance' of structure in the study of turbulent flows in general, and shear flows in particular. We have developed a robust algorithm which 'extracts' regions of concentrated activity in a fluctuating turbulence variable and labels each region individually for quantitative and graphical analysis, and applied the technique to the combined visual and quantitative analysis of vorticity, strain-rate, Reynolds stress and turbulent kinetic energy in the transition for isotropic to shear-dominated homogeneous turbulence. The focus of the second program is on interscale interactions in high Reynolds number turbulence, with a particular focus on the direct interaction between large and small scales in the dynamic evolution of equilibrium and nonequilibrium turbulent flows. Analytical analysis has demonstrated the persistence of these interactions in the high Reynolds number limit and basic analysis of the limiting triadic form of the Navier-Stokes equation has appeared in several publication Based on predictions made from the asymptotic triadic equations, we have analysed the dynamics of direct large-small scale couplings through direct numerical simulations of initially isotropic turbulence forced anisotropically the large scales and found that large scale restructuring can dramatically alter small scale structure and dynamics. Turbulence, Shear flows, Scientific visualization.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1993
- Accession Number
- ADA278269
Entities
People
- James G. Brasseur
Organizations
- Pennsylvania State University