Numerical Study of Flow around Two Circular Cylinders in Tandem, Side-By-Side and Staggered Arrangements

Simulations are presented for flow around pairs of circular cylinders at a Reynolds number of 3900. The flow is assumed to be two-dimensional and incompressible in nature and the simulations are performed using a RANS (Reynolds Averaged Navier Stokes) approach with a k-ε model. Simulations are performed for three different configurations of the cylinders: A tandem configuration where the line joining the centre of the cylinders is parallel to the mean flow direction; side-by-side, where the centre line is perpendicular to the mean flow direction; and staggered where the centre line is an angle α to the flow direction. Simulation results are presented for cylinder separations ranging from 1.125 to 4 diameters and for values of α between 10° and 60°. The results are presented and discussed in terms of the lift and drag coefficients, the Strouhal number, the vorticity field and the flow regimes observed. The results and flow regimes are also compared to previous observations at lower Reynolds numbers to investigate the Reynolds number dependence of the phenomena.