Flow Confinement Effects on the Wake Structure behind a Pitching Airfoil： A Numerical Study Using an Immersed Boundary Method

作     者：Ali Akbar Hosseinjani Ali Ashrafizadeh 

作者机构：Faculty of Mechanical Engineering K. N. Toosi University of Technology Tehran P.O.B. 19395-1999 Iran 

出 版 物：《Journal of Bionic Engineering》 (仿生工程学报（英文版）)

年 卷 期：2017年第14卷第1期

页      面：88-98页

核心收录：

学科分类：0710[理学-生物学] 0831[工学-生物医学工程（可授工学、理学、医学学位）] 07[理学] 09[农学] 0836[工学-生物工程] 0702[理学-物理学] 

主　　题：immersed boundary method pitching airfoil vortex street induced momentum aligned vortex 

摘      要：The flow patterns and wake structures behind a pitching airfoil in an un-bounded domain have been studied extensively. In contrast, the flow phenomena associated with a pitching airfoil near a solid boundary have not been adequately studied or reported. This paper aims at filling this research gap by considering the flow confinement effects on the flow pattern around a pitching airfoil. To achieve this goal, the flow fields around a flapping airfoil in un-bounded, bounded and semi-bounded domains are studied and compared. Numerical simulations are carried out at a fixed Reynolds number, Re = 255, and at a fixed oscillation frequency corresponding to St = 0.22. An accurate immersed boundary method is employed to calculate the unsteady flow fields around the airfoil at various flapping amplitudes. It is argued that two flow mechanisms, here called ＂the interaction effect＂ and ＂the induced reverse flow effect＂ are responsible for the variations of the flow field due to the presence of a nearby solid boundary.