Numerical investigation of flow patterns for staggered cylinder pairs in cross-flow

Numerical simulations of the flow patterns around two staggered circular cylinders in cross-flow are presented for the low subcritical Reynolds number regime. The unsteady two-dimensional Navier-Stokes equations for this flow are solved using a numerical vortex method, which is described in some detail. Detailed numerical results for the flow patterns for different arrangements of the cylinders, at a Reynolds number, Re=800, are presented and compared with existing experimental data. Five distinct flow regimes, depending on the geometrical arrangement of the cylinders, are identified in the simulations, the flow characteristics of the different regimes are discussed in some detail. For the most part, the flow patterns discerned in the numerical investigation are in agreement with previously reported experimental observations, although in some cases the flow patterns are obtained for slightly different cylinder configurations.