This paper analyzes the aerodynamic performance and flow separation characteristics of a rectangular wing for varying Reynolds numbers. The mechanism of separation and its effect on the rectangular wing were simulated in ANSYS FLUENT using K-ω SST turbulence model. A detailed analysis was performed to discuss aspects like the lift and drag force of the wing surface, surface pressure distribution around the wing surface, flow separation characteristics for different angles of attack, velocity profiles at different sections of the wing surface along the chord length, and the effect of wing tip vortices. The simulation results showed that by increasing the angles of attack, the separation point moves towards the leading edge and the onset of stalling is very much closer to the leading edge. Also, the experimental and numerical results indicated that NACA4415 airfoil had enhanced coefficient of lift to coefficient of drag ratio at the angles of attack (AoA) ranging between 4◦ and6◦,which are distinctively advantageous for the better performance of small-scale wind turbine rotors. The experimental and computational results were analyzed in the context of effective change in stalling characteristics at different Reynolds numbers.