variavel0=Gustavo C. R. Bodstein - gustavo@serv.com.ufrj.br EE/COPPE/UFRJ Vanessa G. Guedes - vanessag@cepel.br COPPE/UFRJ Miguel H. Hirata - hirata@iem.efei.br IEM/EFEI Abstract. The study of external incompressible flows at high Reynolds numbers around bluff bodies finds extensive applicability to real-life problems, in addition to the recently renewed scientific interest as a means for testing numerical algorithms. Such flows are characterized by several different regimes that depend on the value of the Reynolds number, ranging from steady Stokes-type flows to strongly unsteady turbulent flows. For a wide range of Reynolds numbers a Von Karman-type periodic wake is formed. In most cases the occurrence of separation makes the prediction of these flows very difficult, and one has to rely on specific experimental data to calculate the aerodynamic forces on the body. Many attempts to numerically simulate most of the flow details have been reported in the literature, and a variety of both mesh-based and mesh-free methods have been used. In this paper we use a new mesh-free two-dimensional discrete vortex method associated to a method of distributed singularities, the Panel Method, to calculate global (e.g. lift and drag coefficients) as well as local (e.g. pressure coefficient) quantities for a high Reynolds number flow around a square cylinder. Lamb vortices are generated along the cylinder surface, whose strengths are determined to ensure that the no-slip condition is satisfied and that circulation is conserved. The impermeability condition is imposed through the application of a source panel method, so that mass conservation is explicitly enforced. The dynamics of the body wake is computed using the convection-diffusion splitting algorithm, where the diffusion process is simulated using the random walk method, and the convection process is carried out with a lagrangian second-order time-marching scheme. Results for the aerodynamic forces and pressure distribution are presented. Keywords. Fluid Mechanics, Aerodynamics, Bluff Bodies, Incompressible Flows, Gas Dynamics.