Aerodynamic and stability characteristics of NACA4412 in ground effects

Abstract Purpose of paper – The potential increase in aerodynamic efficiency whilst operating in close proximity to the ground has stimulated substantial interests in the design and applications of Wing‐In‐Ground (WIG) craft. The purpose of this paper is to investigate the aerodynamic and stability characteristics, such as the Aerodynamic Center of Height (ACH) and the Aerodynamic Center of Pitch (ACP) of a NACA4412 airfoil in ground effect and give clear physical and mathematical definitions of ACH and ACP Design/methodology/approach – Both a panel method and a Finite Volume Method (FVM) have been employed to analyze the aerodynamic and stability characteristics numerically in this paper. Findings – It is found that for the range of heights and pitch angles investigated, ACH of a NACA 4412 airfoil is only a function of pitch angle while ACP is only a function of height. The ACH of a NACA4412 airfoil lies behind the ACP. When viscous effects are taken into account, the ACH of the NACA4412 airfoil moves further forwards due to boundary layer de‐cambering effects. Originality/value – These findings are important for preliminary WIG‐craft design and analysis in term of airfoil selection.