Design Parametric Study of a Compound Wing-in-Ground Effect. I: Aerodynamics Performance

The configuration and service condition of a wing can influence the performance of wing-in-ground effect (WIG) craft. In this study, the aerodynamic performance of compound wings in ground effect was numerically investigated through a parametric design study. The compound wing is divided into three parts with one rectangular wing in the middle and two reverse taper wings with an anhedral angle at the sides. A NACA6409 airfoil was employed as a section of the wing. The design parameters included the span size, anhedral angle, and taper ratio plus two boundary conditions: ground clearance and Reynolds number. The three-dimensional, Reynolds-averaged Navier-Stokes (RANS) equations were solved numerically. A realizable k-epsilon turbulent model was used to compute the effects of the turbulent flow over the wing surface. The computational results of the basic wing were compared with the experimental data of other published works. Next, the aerodynamic performance of the compound wings was computed for various design parameters. Accordingly, all design parameters had effects on the lift-to-drag ratio of the compound wing, although their effects were not equal. The span size of the side wing, anhedral angle, and ground clearance have substantial effects on the lift-to-drag ratio of the compound wing. Two phenomena, namely the ram effect pressure and tip vortex could affect the lift-to-drag ratio of the compound wing in different configurations and conditions. (C) 2015 American Society of Civil Engineers.