In this study, control of flow over a NACA2415 aerofoil which experiences a laminar separation bubble at a transitional Reynolds number of 2x105 is computationally investigated using blowing or suction. In an earlier flow control study which involved the use of a leading edge slat, both the experimental and computational studies demonstrated significantly delayed stall angles. For these flows, employing the recently developed k-kL-ω and k-ω SST transition models were shown to accurately predict the location of the experimentally determined separation bubble. In the present case, a single jet with a width of 2.5% the chord length is placed on the aerofoil's upper surface simulating the blowing/suction control at Re=2x105 and α = 8 degrees. Nearly 200 numerical simulations are carried out a range of parameters of jet locations, Ljet, jet velocity ratios, Rjet and jet angles, θjet are investigated. In the numerical results of blowing/suction, it is shown that the smaller blowing results are better larger blowing velocity ratios while the largest suction results are better
smaller suction velocity ratios independent of the suction jet locations.