基于结构动力学的平板扑翼气动弹性方法研究

Dynamic fluid-structure coupling research for micro flapping wing

由于扑翼机构给定的运动与变形运动的相互耦合,扑翼的运动属于柔性多体动力学问题,使得经典的动力学理论无法适用于扑翼的气动弹性研究。针对扑翼的结构特性,研究了一种适用于扑翼的气动结构耦合计算方法。考虑惯性力、气动力和运动加速度后,利用Hamilton变分原理建立扑翼动力学控制方程,并采用Newmark数值解法进行求解。通过求解三维非定常雷诺平均Navier-Stokes方程获得精确的非定常气动特性。气动网格与结构网格之间的数据传递采用无限平板样条插值(IPS)方法。运用本文方法对做沉浮运动的矩形钢板分别进行了刚性翼和柔性翼的气动分析,计算结果均与实验结果吻合良好,验证了所发展方法的正确性。

Due to the coupling between large prescribed motions and flexible deformation, classical dy- namics theory could not be applied in the flapping wing aeroelastic studies. In this paper, a dynamic fluid- structure coupling computational framework is developed which is able to simulate the complex flow around flexible flapping wings and investigate the effects of the wing flexibility on aerodynamic performance. The equations of motion are derived using Hamilton＇s principle, and a Newmark solution method is used to solve the above equations which takes into account of inertial force and aerodynamic force together. The aerody- namic force is obtained by RANS （Reynolds-Averaged Navier-Stokes） solver. An IPS （Infinite Plate Spline） method is used for data exchange between aerodynamic and structural grids. A loose CFD/CSD coupling method is used, and it only requires 3-4 sub-iterations to get converged. A NACA0012 cross-sectional rectan- gular wing with prescribed pure plunge motion is investigated. Both rigid and flexible wing results are pres- ented, and good agreements between experiment and computation are shown regarding tip displacement and thrust coefficient.