Large Eddy Simulation of Turbulent Flow around a Stationary and an Oscillating Rectangular Cylinder.

Abstract

The application of large eddy simulation (LES) to practical engineering problems has been attempted by many researchers. In recent years, flow fields that have not only simple geometry but also complicated flow structures have been simulated by LES. In this paper, turbulent flow around a stationary and an oscillating rectangular cylinder at high Reynolds numbers of 2.2×104 and 7.14×104 has been analyzed by LES. The main objectives of this work are to compare computed results with experimental values and to prove the applicability of LES to flow induced vibration problems. Drag coefficients, base pressure coefficients and Strouhal numbers were in fairly good agreement with experimental values, while the classical Smagorinsky model was used as a subgrid scale (SGS) model. In cases of flow around an oscillating rectangular cylinder, we successfully simulated the lock-in phenomenon whereby the vortex-shedding frequency equals the oscillating frequency. The width of the lock-in region and phase angles between cylinder displacement and lift coefficient at various oscillating frequencies were in good agreement with experimental results. Both lock-in and nonlock-in states of flow were observed in the vicinity of the boundary frequency of the lock-in region.