Ground effects on flows past NACA0012 and NACA0018 airfoils, are studied at chord-based Reynolds numbers of \(5 \times 10^{4}\) and \(3 \times 10^{5}\) , using Reynolds-Averaged-Navier–Stokes simulations. Gap ratios in the range 0.15–1.0, are considered. The simulations are conducted for two values of angle of attack, \(0^\circ\) and \(10^\circ\) . At a higher value of Reynolds number, lift coefficients decrease more rapidly for the thicker airfoil with decreasing gap ratio, at \(0^\circ\) angle of attack, due to increase in suction pressure on the lower airfoil surface. At \(10^\circ\) angle of attack, positive lift coefficients are obtained that increase more rapidly for the thinner airfoil with decreasing gap ratio, due to increase in positive pressure coefficients on the lower airfoil surface. At a lower value of Reynolds number, the flow is significantly affected due to separation of boundary layers on the lower and upper airfoil surfaces at \(0^\circ\) and \(10^\circ\) angles of attack, respectively.