The Spatial Structure of Intense Foci in a Time-Developing Three-Dimensional Plane Wake

Abstract

Ashurst et al. (1987), studied the alignment of vorticity with the three principal strain directions for forced homogeneous isotropic turbulence and homogeneous shear flow using direct numerical simulation (DNS) data and concluded that the vorticity vector is primarily aligned along the eigenvector of the intermediate principal rate of strain orientation. This finding is contrary to common belief that vorticity tends to align itself in the direction where it is most highly stretched i.e. with the eigenvector corresponding to the largest eigenvalue. This result was also observed by Chen et al. (1990), Sondergaard et al. (1991) and Soria et al. (1994) who applied topological methodology in the study of the small scale motions in incompressible time developing mixing layers using DNS data. Erlebacher & Sarkar (1993) studied the alignment of vorticity with the three principal strain directions for compressible homogeneous turbulence and their result is also in agreement with Ashurst et al. (1987). Tsinober et al. (1992) using grid turbulence measurements have also experimentally confirmed this result.KeywordsDirect Numerical SimulationFocal RegionJoint Probability Density FunctionDirect Numerical Simulation DataIntermediate RateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.