Author(s)

P. Vorobieff, D. Georgiev, & T. Shakeel

Abstract

Bluff-body wakes have been extensively studied for more than a century, however, many issues related to wake instabilities still need elucidation. For a cylinder wake, instabilities develop in directions normal and parallel to the cylinder axis. What is the respective influence of the Former and the latter upon such important parameters as the vortex-shedding frequency? Our experiments with cylinder wakes in a nearly two-dimensional soap film flow show differences between the wake parameters in two- and three-dimensional (2D and 3D) wakes. In 2D, there is no evidence of discontinuities in the dependence of the dimensionless vortex-shedding frequency (the Strouhal number St) upon the Reynolds number Re due to spanwise instabilities. For Re1200. We find the dimension less down stream distance to the onset of the second wake to scale with Re-’”. Finally, we present previously unknown Features of the interaction of 2D wakes, such as coupling between disordered structures in the far wake.

Keywords