The applicability of numerical simulations for the prediction of the flow field of exhaust openings was examined. Numerical calculations were conducted for two-dimensional plain and flanged slots, plain and flanged circular openings and three-dimensional plain and flanged rectangular openings. The air flows were simulated by the FLUENT computer code based on the finite difference method, using the k-ε turbulence model. The accuracy of the simulations was determined by comparing the predicted results with potential flow solutions and experimental results. For flanged openings, the agreement between numerical simulations and potential flow solutions was good. For plain openings the agreement was satisfactory.