Self-adaptive elastic flaps with bending and torsion for 3D blunt body drag reduction

This study investigates the potential for drag-reduction of low-mechanical-order, self-adaptive control systems, consisting of hinged flaps attached along the edges of the rectangular base of a canonical blunt body. Comparative experiments are conducted in a wind tunnel under crosswind conditions at a Reynolds number of R e = 2.13 × 10 5 . The flaps, made of rigid rectangular panels, are mounted in three configurations: rigidly fixed, flexibly hinged with a single degree of freedom in bending, a