Akademik Veri Yönetim Sistemi
Journal of Wind Engineering and Industrial Aerodynamics, cilt.273, 2026 (SCI-Expanded, Scopus)
Flow characteristics of a circular cylinder equipped with triple longitudinal perforated fins were experimentally investigated at a subcritical Reynolds number of 5000. The effects of fin permeability and orientation are systematically examined for four perforation ratios (β = 0, 0.1, 0.3, and 0.5) and a wide range of angles of incidence. The wake characteristics were investigated by employing force measurements and particle image velocimetry (PIV), and its energy dominant features were explored through proper orthogonal decomposition (POD). The modified cylinders attenuate vortex street compared to bare cylinder, resulting in lower Strouhal numbers (St), but the decrease ratio depends on fin orientation and perforation ratio. Besides, a drag penalty occurs with the vortex suppression. Quantitatively, the solid fin (β = 0) configuration decreased St by 51% but caused a 190% increase in the drag coefficient (CD). Introducing permeability mitigates this penalty, the highest perforation ratio (β = 0.5) reduced St by 32% while limiting the CD increase to 110% due to local momentum exchange thorough the fins’ holes. At the near wake region, this highest perforation ratio can reduce turbulent kinetic energy by up to 87%. Also, modified cylinders exhibited attenuated velocity recovery and elongated wake formation, while POD analysis suggests that perforated fins weaken the coherence of dominant wake structures by redistributing energy toward higher order modes. Consequently, permeability and orientation serve as coupled control parameters rather than independent design variables. While the effectiveness remains sensitive to the configurational setup, perforated fins appear to offer a viable passive strategy for wake modulation in flow control applications.