Flow behind bluff bodies in side-by-side arrangement

The present investigation deals with the shedding of vortices and flow interference between two circular cylinders in a side-by-side arrangement. Simulations are carried out using commercial Computational Fluid Dynamics (CFD) code FLUENT-6.2. The flow field around the cylinders is modeled in two-dimensions with the axis of the cylinder perpendicular to the direction of flow. The cylinder is modeled as a circle and a square flow domain is created around the cylinder. The calculations are carried out on a quadrilateral mesh. The simulations are performed for a Reynolds number of 200. The mesh is finer close to the cylinder wall in order to have a better description of the boundary layer. Contours of vorticity, variation of lift and drag coefficients, force time histories are presented. A mean repulsive lift force exists between the cylinders and the lift force steadily decreases with increasing length to diameter ratio. For length to diameter ratio ≤ 2.0, flopping phenomenon is observed whereas for length to diameter ratio > 2.0, the lift fluctuation is synchronized and is in antiphase. The results of the present work show that the drag coefficient is slightly higher for length to diameter ratio of 2.0. Beyond this ratio, the drag coefficient on either cylinder falls. For length to diameter ratio of 3.0 and 4.0, the power spectrum estimation of the lift coefficient shows a very distinctive peak at Strouhal number of 0.21. © School of Engineering, Taylor's University.