Experimental and numerical study of a scaled Airfish 8 wing-in-ground vehicle

This paper investigates the influence of a stationary ground plane on the performance of a scaled-down Airfish 8 wing-in-ground vehicle at Reynolds numbers Re of 200 000, 250 000, and 300 000 in cruise. Experimental results show that reducing the spacing between the vehicle and the stationary ground plane leads to a substantial lift augmentation of up to ∼50% at the smallest spacing h investigated: h/c̄=0.25, where c̄ is the mean aerodynamic chord. In comparison, the corresponding increase in total drag remains moderate, ranging from ∼10%–15%. While the Spalart–Allmaras turbulence model does not fully capture the Re effect, it demonstrates reasonable agreement with experimental data. The ground plane creates an “air tunnel” effect, enhancing static pressure on the fuselage and wing surfaces, particularly when the vehicle is near the ground. This effect increases lift, slightly raises pressure drag, and reduces viscous drag, leading to a moderate overall increase in total drag. Additionally, the ground plane alters the ground vortex pattern, intensity, and location, with secondary impacts on the tip vortex and stabilizer vortex. These findings lay the groundwork for improving the performance of Airfish 8 in ground effect.