Abstract

The flow around a circular cylinder at Reynolds numbers near the drag crisis was numerically simulated based on a dynamic Smagorinsky Large Eddy Simulation (LES) model at two Reynolds of Re = 1.0 × 105 and 6.0 × 105. The flow structures and the hydrodynamic force on the cylinder were analyzed. The numerical results show that the results at Re = 1.0 × 105 follow the key feature of subcritical turbulent flow and the results with Re = 6.0 × 105 capture the main features of the supercritical flow. This demonstrates that the Dynamic Smagorinsky LES model is a suitable numerical method for exploring high Reynolds flow around a circular cylinder.

Introduction

Slender structures are commonly used in civil, mechanical and offshore engineering, such as skyscrapers, chimneys, tubes in heat exchangers, bridge piers, subsea pipelines, risers and supporting frames of offshore platforms. Due to the strong engineering application background, hydro-/aerodynamics associated with slender structures have been widely researched. The flow around an isolated cylinder involves most of the generic flow features (flow separation, vortex shedding, recirculation, transition of turbulence within the wake and in the boundary layer), thus providing an excellent model for gaining insight into fluid mechanics around structures. As an important flow-structure interaction model, large amount of research about flow around circular cylinders has been published (Sumer and Fredsøe 1997, Zdravkovich 2003).

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