Ground effect on a cropped slender reverse delta wing with anhedral and Gurney flaplike side-edge strips

Abstract

The ground effect on the aerodynamic coefficients of a cropped slender reverse delta wing equipped with anhedral and Gurney flaplike side-edge strips was investigated experimentally at Re = 3.82 × 10⁵. In a free stream, the 30% cropping was found to cause a minor reduction in lift C_L and drag C_D coefficients but a promoted stall compared to the noncropped wing. The anhedral caused further C_L decrease and C_D increase. Meanwhile, the application of side-edge strips produced a significantly increased C_L and C_D with a minor change to the C_L/C_D ratio as compared to the baseline wing. In ground effect, the cropped wing was, however, found to generate more lift compared to the noncropped wing as the ground was approached. The joint anhedral and SES produced a great increment in both C_L and C_D but a virtually unchanged C_L/C_D ratio compared to their outside ground effect counterparts. The larger the side-edge strips’ height the larger the increase in C_L. In short, the cropping led to a weight reduction while the addition of anhedral and SES produced a large lift augmentation of the Lippisch-type wing-in-ground effect craft.