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

Abstract

This paper focuses on the development of a model to represent the 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 that 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). The 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 above ground were obtained along with the derivatives during these maneuvers. The mathematical model presented herein is capable of modeling unsteady aerodynamic phenomena in ground effect at high angles of attack. When this model was used in the static ground effect, values of equal to or greater than 0.999, 0.981, and 0.993 were obtained for lift, induced drag, and pitching moment coefficients, respectively. In the dynamic ground effect, the model can adjust the aerodynamic coefficient during the maneuvers.