Bluff-body Wake Evolution And Interaction In Two Dimensions

Abstract

disordered structures in the far wake. unknown Features of the interaction of 2D wakes, such as coupling between the onset of the second wake to scale with Re-’”. Finally, we present previously flows, it persists to Re>1200. We find the dimensionless downstream distance to wake), which exists in 3D only for low Reynolds numbers (Rec300).In soap film striking feature of the far wake is the onset of the secondary vortex street (second the cylinders (far wake region) and interaction of multiple wakes. The most driven instabilities. We also examine the features of 2D wakes far downstream of dependence of St upon Re to weaken at higher Re is attributable entirely to shearremains valid for 2D data. In the absence of 3D effects, the trend of the not describe the behaviour of 3D flow for higher Re, however, we show that it from 2D. A recently developed fit for St in terms of Ree”’ valid For Re-480 does neutrally stable to spanwise perturbations and thus not substantially different Reynolds number Re due to spanwise instabilities. For Re<lSO, the 3D flow is dimensionless vortex-shedding frequency (the Strouhal number St) upon the In 2D, there is no evidence of discontinuities in the dependence of the between the wake parameters in two- and three- dimensional (2D and 3D) wakes. with cylinder wakes in a nearly two-dimensional soap film flow show differences such important parameters as the vortex-shedding frequency? Our experiments cylinder axis. What is the respective influence of the Former and the latter upon cylinder wake, instabilities develop in directions normal and parallel to the however, many issues related to wake instabilities still need elucidation. For a Bluff-body wakes have been extensively studied for more than a century,