Design Parametric Study of a Compound Wing-in-Ground Effect. II: Aerodynamics Coefficients

Abstract

The aerodynamic behavior of the wing-in-ground effect can be affected by its configuration. This configuration is potentially the most influential parameter for the performance and stability of the wing-in-ground effect craft. As a continuation to the authors’ previous works, in this research, the aerodynamic coefficients of the compound wing have been numerically investigated through the design parametric study in ground effect. The aerodynamics performances of the compound wing have been computed and the effects of various design parameters on the lift-to-drag ratio have been discussed in the previous paper. First, this paper validates the prediction method by comparing the lift coefficient of a rectangular wing with NACA 6409 airfoil for different angles of attack with an aspect ratio of 1.25 and ground clearance of 0.15. Then, the aerodynamic coefficients of the compound wing are computed over a range of various design parameters. As expected, all design parameters have effects on the aerodynamic coefficients. However, the effects of design parameters on the aerodynamic behavior of the compound wing are not equal. It was found that the span of the side wing, anhedral angle, and ground clearance have considerable effects on the ram effect pressure and the tip vortex of the compound wing.