Reynolds number (Re) effects on low-speed vortical flows over 3.5-caliber, tangent-ogive cylinders at two angles of attack (α = 20 and 30 deg) are computationally assessed for ReD =0.2-3 million (D: maximum diameter). The flowfield results are steady-state solution to the three-dimensional, incompressible Navier-Stokes equations in their thin-layer approximation. Using a properly modified algebraic turbulence model, the numerical results are in good to excellent agreement with experiments. For the first time, a crossflow separation pattern, which consists of a laminar separation bubble with a subsequent transition in the separating shear layer that forms a primary vortex, has been modeled. The discussion of the computed results includes a rigorous assessment of the effects of gridding and of turbulence modeling. © 1990 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.