隐身反设计下飞翼布局气动与隐身综合设计

Integrated design on aerodynamic and stealthy of flying wing unmanned aerial vehicle based on stealthy inverse design method

为同时获得良好的气动和隐身性能,基于双发动机布局下飞翼无人机大鼓包式机身,采用隐身反设计思路,开展了飞翼布局气动与隐身综合设计与分析研究,提出了一种减小翼型前缘半径的机身前缘类"鹰嘴"形飞翼布局优化构型.分别采用CFD(计算流体力学)方法对M6机翼进行气动数值模拟方法验证,以及基于FEKO软件中MLFMM(多层快速多极子方法)和PO(物理光学法)对圆柱体和某飞翼布局缩比模型进行隐身数值计算方法验证,并利用该方法获得了飞翼布局无人机气动与隐身综合特性.结果表明:建立的气动与隐身数值模拟方法计算结果与实验吻合较好,数值计算方法是可靠的;基于隐身反设计思路构建的机身前缘类"鹰嘴"形飞翼布局设计不仅纵向气动特性略微提升,且前向(-25°~25°)隐身性能明显提高,充分表明了隐身反设计思路的有效性;前缘类"鹰嘴"形设计主要影响机身表面压力分布,并有助于提升升阻特性;前缘类"鹰嘴"形设计比传统钝形前缘设计在不同频率和不同滚转角下隐身特性均有所提高.

To obtain both good performance on both aerodynamic and stealthy,integrated design and analysis on aerodynamic and stealthy characteristics for flying wing unmanned aerial vehicle (UAV) is conducted based on stealthy inverse design method,focusing on the big bump in the fuselage of twin-engine layout flying wing UAV.Then a kind of fuselage with leading edge similar to eagle mouth is proposed,whose leading edge radius of airfoil is decreased.Using computational fluid dynamics (CFD) method,the numerical simulation is verified on M6 wing.Physical Optics (PO) and Multilevel Fast Multipole Method (MLFMM) are chosen for numerical study on the stealthy performance of cylinder and a certain scale model of flying wing UAV.Moreover,the verified methods are applied to study the aerodynamic and stealthy characteristics of flying wing UAV.The results show that the aerodynamic and stealthy calculation result is close to the experiment data,indicating that the numerical simulation method is valid.Not only the longitudinal aerodynamic performance of flying wing UAV with fuselage leading edge similar to eagle mouth increases appreciably,but also its stealthy performance improves significantly in the forward direction with the azimuth angle from-25° ~ 25°.In addition,it indicates that the stealthy inverse design method is effective.The design with leading edge similar to eagle mouth mainly affects the pressure distribution of fuselage,and it is helpful to advance the lift/drag characteristic.At the same time,the stealthy performance of the optimize design is better than the traditional blunt leading edge at different frequencies and rolling angles.