A parametric study concerning the flow around rectangular prisms of different aspect ratios (1:1, 1:1.5, 1.2, 1:3, 1:4) is conducted numerically at a Reynolds number of 10(5). The Navier-Stokes equations in the large eddy simulation (LES) framework are solved using a finite volume method. The Smagorinsky closure model is used for representing the subgrid scale viscosity. The simulated results clearly demonstrate the influence of the aspect ratio on the velocity field around prisms. Flow reattachment is observed in the mean how for prisms with aspect ratios of 1 :3 and 1 :4. This trend in the mean velocity field is corroborated by the mean and RMS distribution of pressure over the prism surface. The numerical results show a good agreement with the available experimental data. (C) 1998 Elsevier Science Ltd. All rights reserved.