Ground effect on flow behavior and aerodynamic characteristics of a slender delta wing

In this study, the contribution of ground effect to the development of vortical flow over a slender wing with a sweep angle of Λ = 70° was investigated using Computational Fluid Dynamics (CFD) methods. The influence of ground proximity on the flow characteristics and aerodynamic performance of a slender delta wing was examined in detail. To elucidate the flow structure more comprehensively, quantitative results were presented for angles of attack (α) of 0°, 15°, 25°, 35°, and 45°. The distance between the delta wing and the ground surface, denoted as h, was non-dimensionalized by the wing chord length c, and h/c ratios of 0.1, 0.25, 0.55, and 1.5 were selected for comparison, including a reference case without ground effect (GFE). The Reynolds number used in the CFD analysis was fixed at Re = 2.81 × 10⁵. The results indicate that as the delta wing transitions from the free-stream region to the near-wall boundary layer region, particularly at h/c = 0.1, the intensity of the vortices over the wing surface gradually diminishes. Furthermore, it was observed that aerodynamic efficiency improves as the wing approaches the ground, a phenomenon attributed to the formation of a dynamic air cushion effect.