摘要
为解决低雷诺数下仿生飞行器设计中边界层流动分离这一热点问题,仿照鸟类次级羽毛的流动控制机制,提出了利用翼型下表面柔性襟翼进行非定常流动控制的方法。建立了一种以浸入边界法为核心的通用IB-LB-FEM流固耦合数值模拟框架,并系统研究了下表面柔性襟翼位置和刚度系数对NACA0012翼型非定常流动的影响,揭示了柔性襟翼流固耦合效应下的变形规律及其非定常流动控制机理。研究结果表明:当柔性襟翼靠近尾缘时,其对翼型气动性能的影响较为明显,其中最大平均升阻比相比无襟翼翼型提升了33.32%;下表面柔性襟翼并没有直接参与翼型表面流动分离的控制,但其通过扰动翼型下表面的非定常流动在襟翼后方形成新的流动分离从而影响了翼型的气动特性。此外,改变下表面柔性襟翼的刚度系数,将充分利用流固耦合特性有效改善翼型的气动性能。研究对于深入柔性襟翼流动控制机理,解决仿生飞行器的流动分离提供了新的研究思路。
In order to solve the hot issue of the boundary layer flow separation in the design of bio-inspired aircraft at low Reynolds number,a method of unsteady flow control using flexible flaps on the lower surface of the airfoil was proposed in the paper based on the flow control mechanism of bird secondary feathers.Specifically,a general IB-LB-FEM fluid-structure coupling method with the immersed boundary method as the core was established,the effect of the position and stiffness coefficient of the flexible flap on the unsteady flow of NACA0012 airfoil was systematically studied,and the deformation law and unsteady flow control mechanism of the flexible flap under fluid-structure coupling were revealed.The results show that the influence of the flap near the trailing edge of the airfoil on the aerodynamics of the airfoil is more obvious with the maximum average lift-drag ratio being 33.32%higher than that of the airfoil without flaps;the flexible flap on the lower surface does not directly participate in the control of the flow separation on the surface of the airfoil,but it can form a new flow separation behind the flap by disturbing the unsteady flow on the lower surface of the airfoil,thus affecting the aerodynamics of the airfoil;by changing the stiffness coefficient of the flexible flap on the lower surface of the airfoil,the fluid-structure coupling characteristics of the flexible flap can also effectively improve the aerodynamics of the airfoil.Focusing on studying the flow control mechanism of the flexible flap,the study can provide a new research idea for solving the flow separation of bionic aircraft.
作者
孟俊苗
韩佳坤
陈刚
MENG Junmiao;HAN Jiakun;CHEN Gang(School of Highway,Chang’an University,Xi’an 710064,China;School of Aerospace Engineering,Xi’an Jiaotong University,Xi’an 710049,China;State Key Laboratory for Strength and Vibration of Mechanical Structures,Xi’an Jiaotong University,Xi’an 710049,China;Shaanxi Key Laboratory for Service Environment and Control of Flight Vehicles,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2023年第9期22-30,共9页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(52192633,92152301)
陕西省杰出青年科学基金资助项目(2022JC-03)。
关键词
柔性襟翼
浸入边界法
流动控制
流固耦合
非定常流动
flexible flap
immersed boundary method
flow control
fluid-structure coupling
unsteady flow
