Quantitative study on the flow control of a 1:2 rectangular cylinder based on the leading-edge suction

Abstract

The present study employed the leading-edge suction flow control on a 1:2 rectangular cylinder to control its unsteady aerodynamics. To study the suppression on aerodynamic forces, the surface pressures were measured at the Reynolds number of 1.28 × 104. A dimensionless suction momentum coefficient (Cμ) was defined to quantify the suction flow rate. The detailed flow visualization was conducted on the wake flows as well as the leading-edge separated flows to reveal the control mechanism. The proper orthogonal decomposition (POD) analysis was conducted on the wake flows to study the modal transformations. Results show that the leading-edge suction flow control could significantly affect the flow separation-reattachment characteristics and the present control processing could be divided into five stages with increasing Cμ. The lift fluctuation could reach a maximum reduction of 66.4%. Meanwhile, the flow separation at the leading edge was gradually suppressed and eliminated with increasing Cμ. The wake flow was compressed in the transverse region and suppressed in the turbulent kinetic energy (TKE) as well as the Reynolds shear stress (RSS), which should be responsible for the suppression on the lift fluctuation.