Ground effect on lift of thick wing airfoil

The paper investigates the influence of the ground on the airfoil lift. The Numerical Analytic Method (NAM) and the Discrete Vortices Method (DVM) are developed for simulating the flow around an airfoil when it is in the close proximity to the ground. The author proposes the NAM for modeling the flow around the airfoil near the ground and analyzes two approaches to solving the problem of Wing-in- Ground (WIG). The first method is based on the simulation of the ground surface, while the second one uses the reflection method. It has been shown that the increasing in the relative airfoil thickness reduces the positive WIG lift effect. It is also established that there is an optimal airfoil angle of attack at which the maximum lift occurs near the ground.