Nonlinear Aerodynamic Model in Dynamic Ground Effect at High Angles of Attack

Abstract

This paper focused on the development of a model to represent longitudinal aerodynamics of a wing and/or flight vehicle in ground effect when height is a function of time including high angles of attack. A general aerodynamic model of a wing and/or airplane in ground effect which includes high angles of attack was created. The aerodynamic coefficients of wings studied herein were obtained by the unsteady vortex lattice method with Kirchhoff-based correction (UVLM-K). Wind tunnel measurements presented in the literature were used to validate the UVLM-K. Then, a rectangular wing was simulated at high angles of attack in takeoff and flare, and the aerodynamic characteristics at different heights aboveground were obtained along with the h derivatives during these maneuvers. The mathematical model presented herein is capable to model unsteady aerodynamic phenomena in ground effect at high angles of attack. When this model was used in static ground effect, values of R2 equal to and greater than 0.999, 0.981, 0.993 were obtained for lift, induced drag, and pitching moment coefficient, respectively. In dynamic ground effect, the model can adjust the aerodynamic coefficient during the maneuvers.