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Open Access Issue
Effect of bleeding on aerodynamics of non-slender delta wing in ground effect
Chinese Journal of Aeronautics 2026, 39(5)
Published: 29 September 2025
Abstract Collect

This article experimentally investigates the influence of the passive bleeding technique on the flow structure and aerodynamic coefficients of a non-slender delta wing with a 45-degree sweep angle in Static Ground Effect (SGE). The study was conducted under both static and dynamic boundary conditions using a fixed plate and a moving belt, respectively. Particle Image Velocimetry (PIV) and force/moment measurements were performed in a low-speed wind tunnel at Reynolds number, Re = 9 × 104. The results indicate that bleeding in ground effect shifts the focal point toward the leading-edge and increases inboard/outboard vorticity at low angle of attack α = 6°, which may enhance the shear-layer feeding mechanism. At high angle of attack α = 17°, bleeding in ground effect reduces the adverse effects introduced by the ground proximity, potentially delaying stall. Regarding aerodynamic coefficients, bleeding overall reduces their sensitivity to the ground. In addition, the dynamic boundary condition results in decreased magnitudes of the aerodynamic coefficients and does not negatively affect the stall angle delay provided by the bleeding mechanism, unlike the static boundary condition.

Open Access Full Length Article Issue
Aerodynamics of non-slender delta and reverse delta wings: Wing thickness, anhedral angle and cropping ratio
Chinese Journal of Aeronautics 2023, 36(4): 79-91
Published: 25 June 2022
Abstract Collect

The effects of thickness-to-chord (t/c) ratio, anhedral angle (δ), and cropping ratio from trailing-edge (Cr%) on the aerodynamics of non-slender reverse delta wings in comparison to non-slender delta wings with sweep angle of 45 ° were characterized in a low-speed wind tunnel using force and pressure measurements. The measurements were conducted for total of 8 different delta and reverse delta wings. Two different t/c ratios of δ = 5.9% and 1.1%, and two different anhedral angles ofδ = 15° and 30° for non-cropped and cropped at Cr = 30% conditions were tested. The results indicate that the reverse delta wings generate higher lift-to-drag ratio and have better longitudinal static stability characteristics compared to the delta wings. The wing thickness has favorable effect on longitudinal static stability for the reverse delta wing whereas longitudinal static stability is not influenced by wing thickness for the delta wing. For reverse delta wings, the anhedraled wing without cropping has adverse effect on aerodynamic performance and decreases the lift-to-drag ratio. Cropping in anhedraled wing causes significant improvement in lift-to-drag ratio, shift in aerodynamic and pressure centers towards the trailing-edge, and enhancement in longitudinal static stability.

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