2D numerical simulation of slow flow past circular cylinders

Two dimensional slow viscous flows past one or two circular cylinders are investigated by direct numerical simulation with incompressible Navier-Stokes equations. Steady uniform flows are obtained from the pressure difference imposed at the boundaries. In the simulation of one cylinder, drag coefficients are in good agreement with those obtained in experimental and other numerical studies for relatively low Re (1 {precedes or equivalent to} Re {precedes or equivalent to} 10²), and those in theoretical studies for very low Re (O(10^-2 {precedes or equivalent to} Re {precedes or equivalent to} 1). In the case of two cylinders, we successfully visualize flow separation patterns which are similar to those in experimental and theoretical studies. We also investigate the flow separation patterns and drag coefficients of the cylinders in detail, and obtain the new flow separation pattern in some parameter space.