Ground Effect Investigation on the Aerodynamic Airfoil Behavior Using Large Eddy Simulation

The underlying physics ever behind the aerodynamics of an airfoil in ground effect (GE) are still not fully resolved. In this work, the aerodynamics for an airfoil in GE is investigated computationally for both transitional and turbulent flow regimes. Large eddy simulation (LES) is employed to explore the flow physics around a NACA0012 airfoil in ground vicinity, which is commonly used in wind energy applications. The angle of attack (AoA) is fixed at AoA = 10 deg, while the flight height to chord ratio (h/c) is variable. An analysis is conducted for the aerodynamic forces, i.e., the lift (CL), and the drag (CD). The behavior for the skin fiction drag (CDf) is explored in the light of the flow physics near the ground. In addition, the vortex shedding behavior is estimated at different height (h/c) for the transitional and turbulent flow regimes. At h/c = 0.2, the friction drag (CDf) is improved by 9.6% and 16.3% for the transitional and turbulent flow regimes, respectively. The results show that the frequencies for the vortex shedding decline significantly near the ground. This decline is correlated with the larger vortical structures and vortex developing mechanism.