Flow interaction behind two circular cylinders of equal diameter - a numerical study

Abstract

Incompressible flows past two circular cylinders placed side by side in a uniform stream were investigated numerically by the discrete vortex model. The calculations were carried out at T d = 1.25, 1.75, 3.0 and 3.5, where T is the transverse distance between cylinder centers and d the cylinder diameter. The flow development was initiated by imposing a perturbation of short duration on the separated shear layers from the cylinders and four modes of perturbation were tried. For the mode 2 perturbation of T d = 1.25, 3.0 and 3.5, the single vortex street, out-of-phase and in-phase vortex shedding modes were observed, respectively, agreeing with the well-known experimental results. At the bistable flow of T d = 1.75 an asymmetric mode of vortex shedding was observed and the possible effects on flow parameters such as lift and drag were discussed. © 1995.