Influence of periodic forcing on laminar separation bubble

Abstract

Flow control plays an important role in enhancing aerodynamic characteristics of airfoils such as reducing skin-friction drag, advancing or delaying transition, preventing or triggering separation, and enhancing the lift coefficient. In the review paper of Gad-el-Hak and Bushnell (J Fluid Eng 113, 5–30 (1991)) [6], they provided an extensive review of flow control techniques such as blowing (J Aircr 25, 817–821 (1989)) [11], suction (AIAA J 25, 759–760 (1987)) [13] acoustic excitation (J Fluid Mech 182, 127–148 (1987)) [18], periodic forcing excitation by imposing an oscillating wire or flap upstream the separation location (AIAA J 24, 1956–1963 (1986)) [15], (Phys Fluids Fluid Dyn 2, 179–181 (1989)) [10], (AIAA J 27(6), 820–821 (1989)) [5] and utilization of magnetic field through plasma actuators as documented by Post and Corke (AIAA J 42(11), 2177–2184 (2004)) [12] and Huang et al. (AIAA J 44(7), 1477–1487 (2006)) [7].