旋翼/机身气动干扰的数值模拟

通过求解粘性非定常可压缩N-S方程,发展了旋翼/机身气动干扰的数值模拟方法,主要技术措施包括:(1)通过ADT数据结构,建立了高效的多块对接网格动态重叠技术;(2)在可压缩方程求解中引入低速预处理方法,克服低速流场求解时的刚性问题;(3)加入了多重网格方法,提高收敛效率;(4)湍流模型方程求解需要反复计算壁面最近距离,采用Wigton的优化算法很大程度上提高了计算速度。利用建立的计算方法对佐治亚大学(GIT)旋翼/机身干扰模型进行了数值模拟,分别比较了机身表面的平均压力分布、旋翼的下洗流场以及非定常压力脉动,对干扰现象及其流动机理进行了分析。

Numerical Simulation of Rotor/Airframe Aerodynamic Interaction

Viscous,unsteady compressible N-S equations and moving overset grid methodology are adopted for the numerical simulation of rotor airframe interaction,and some improvements are proposed to improve the efficiency and accuracy.These modifications include:(1)low speed preconditioning are implemented in the solution of compressible equations to overcome the stiffness when solved in incompressible regions;(2)multigrid methods are used to speed up the convergence;(3)the nearest distances from any cell to wall are calculated repeatedly because of grids moving,Wigton's optimized methods are implemented to deal with the difficulties.GIT rotor/airframe interactions are simulated by the methods,the averaged surface-pressure distributions on the airframe,the down wash velocities and pulsed pressure are compared with experimental values,the interaction phenomena and vorticity patterns that impinge on the airframe are analyzed.