Mean flow characteristics of two-dimensional wings in ground effect

ABSTRACTThe present study numerically investigates the aerodynamic characteristics of two-dimensional wings in the vicinity of the ground by solving two-dimensional steady incompressible Navier-Stokes equations with the turbulence closure model of the realizable k-ε model. Numerical simulations are performed at a wide range of the normalized ground clearance by the chord length (0.1≤h/C ≤ 1.25) for the angles of attack (0° ≤ α ≤ 10°) in the pre-stall regime at a Reynolds number (Re) of 2×106 based on free stream velocity U∞ and the chord length. As the physical model of this study, a cambered airfoil of NACA 4406 has been selected by a performance test for various airfoils. The maximum lift-to-drag ratio is achieved at α = 4° and h/C = 0.1. Under the conditions of α = 4° and h/C = 0.1, the effect of the Reynolds number on the aerodynamic characteristics of NACA 4406 is investigated in the range of 2× 10 5 ≤ Re ≤ 2× 109. As Re increases, Cl and Cd augments and decreases, respectively, and the lift-to-drag ratio increases linearly.