基于CFD/CSD方法的蜻蜓柔性翼气动特性分析

给出了一种基于计算流体力学/计算结构力学(CFD/CSD)的双向流固耦合方法.通过交替数字二叉树(ADT)搜索技术识别流固网格之间的宿主-受体关系.采用局部插值算法完成两套网格系统之间的数据交换,并使用Delaunay图映射方法来完成气动网格的移动.将自编的非线性结构有限元程序、接口程序与南京航空航天大学(NUAA)微型飞行器中心的流体计算程序3D2MUFS相连接,应用于蜻蜓柔性翼拍动飞行的气动计算中.计算结果表明:柔性变形使得蜻蜓翼的时均举力系数从0.31提高到0.53,时均推力系数从0.07提高到0.13,证实了柔性变形能改善扑翼的气动性能.

Analysis of aerodynamic characteristics of flexible wing of dragonfly based on CFD/CSD method

A methodology of fluid-structure bi-directional interaction based on computational fluid dynamics/computational structure dynamics (CFD/CSD) was presented. The donor-receptor relationship between two sets of grid system was identified by alternating digital tree (ADT). The local interpolation methods were used for data exchange between these two sets of grids. Flow with moving boundaries was dealt with by Delaunay graph mapping method. The code for nonlinear structural finite element and information transfer was developed and used to connect with the code of flow solver 3D2MUFS developed in the Micro Air Vehicle Center of Nanjing University of Aeronautics and Astronautics (NUAA). It was applied to the aerodynamic computation of dragonfly flapping flight with flexible wing. Results show that the time-averaged vertical force coefficient of the dragonfly wing increases from 0.31 to 0.53, and the time-averaged thrust coefficient increases from 0.07 to 0.13 by flexible deformation. This confirms that the flexible deformation can improve the aerodynamic performance of flapping wing.