Drag Reduction of an Ahmed Body Using Combined Steady Blowings

Active drag reduction of an Ahmed body with slant angle of 25° has been experimentally investigated at a Reynolds number Re of 1.67 × 10⁵, based on the square root of the body cross-sectional area. A combination of steady blowing is deployed along the upper and two side edges of the rear window and the upper edge of the vertical base, resulting in a maximum reduction in drag by 25%, which is higher than those reported in the literature for the same body. Measurements are conducted using particle image velocimetry. A marked modification is identified on the separation region over the rear window, the upper and lower recirculation bubbles behind the vertical base, and the C-pillar vortices, which is connected to the high drag reduction.