Numerical simulation of wings in steady and unsteady ground effects

Abstract

A numerical simulation of steady and unsteady ground effects is developed. The simulation is based on the general unsteady vortex-lattice method and is not restricted by planform, angle of attack, sink rate, dihedral angle, twist, cross wind, etc., as long as stall does not occur. The present computed results are generally in close agreement with limited exact solutions and experimental data. The present results show the influences of various parameters on the aerodynamic coefficients for both steady and unsteady flows. Generally, the aerodynamic coefficients increase with proximity to the ground, the greater the sink rates the greater the increases, increasing the aspect ratio increases both the steady and unsteady ground effects for both rectangular and delta planforms. The steady ground effect increases the rolling moment and the side force. The present results serve to demonstrate the potential of the present approach.