柔性扑翼气动结构耦合特性数值研究

摘要

微型扑翼体积小、重量轻，其柔性变形对气动特性有显著的影响。通过求解雷诺平均 N-S 方程（Reynolds－Averaged Navier-Stokes，RANS）和结构动力学方程，对微型柔性扑翼飞行器的气动结构耦合特性进行了数值模拟研究。针对微型扑翼的大幅运动，发展了适用于扑翼的气动结构耦合数值计算方法，研究了微型扑翼的气动结构耦合特性。通过求解雷诺平均 Navier-Stokes（RANS）方程得到微型扑翼的非定常气动特性；利用哈密顿原理（Hamilton Principle）推导了扑翼的结构动力学方程，采用结构有限元方法对该动力学方程进行离散并求解，得到扑翼的动态结构特性；采用松耦合方法进行迭代。计算结果与风洞实验结果相比吻合良好，验证了所发展方法的有效性。在此基础上研究了惯性力和关键运动参数对柔性扑翼气动及结构特性的影响规律，有助于比较详细、全面地了解微型扑翼的气动机理，为柔性扑翼的设计提供了参考依据。%Due to the small size and light weight,flexible deformation plays an important part in flapping wing aerodynamics.the aero-elastic performances of Flapping-wing Micro Air Vehicle (FMAV)are researched by solving the Reynolds-Averaged Navier-Stokes (RANS ) equations and structural dynamic equations.An aerodynamic-structural coupling computational framework is developed,which is able to simulate aerodynamic-structural coupling characteristics of flexible flapping wings.The flapping wing′s unsteady aerodynamic characteristics is obtained by solving Reynolds Average Navier-Stokes (RANS)equations.Structural dynamic equations capable of describing the flapping wing′s movement are derived by using Hamilton principle,then discreted through finite element method and solved by Newmark solution to get structural characteristics.Loose coupling method is used.On the basis of the above work,CFD/CSD (Computational Fluid Dynamics/Computational Structural Dynamics)grid data exchange method, dynamic grid technology as well as coupling method are further investigated,and finally a complete set of CFD/CSD coupling solver is developed.Computational results show good agree-ment with experimental results,which prove that the method developed in this paper are valid and suit for simulation of flexible flapping wing.Effect of inertia loads and kinetic parameters are also investigated,which can help to understand the mechanisms of flexible flapping wing′s aero-elasticity and give a guidance in the design of flexible flapping wing.