细长旋成体单孔位微吹气扰动控制的数值研究

【作者】 孟轩；

【导师】 陈志敏；

【作者基本信息】 西北工业大学 ， 流体力学， 2007， 硕士

【摘要】 本文以现代大迎角飞行器前体非对称背涡产生随机侧向力现象为研究背景，以一个尖拱形细长旋成体模型为研究对象，以数值模拟为主要研究手段，研究大迎角细长体的尾流场非对称背涡的空间结构。通过对N-S方程求解，详细研究了无侧滑条件下细长旋成体在大迎角情况下背风区附体和脱体涡系的空间演化规律，加深了对细长旋成体背风区非对称涡系空间模型以及涡系之间的相互干扰作用的认识，验证了单孔位微吹气扰动控制方法的有效性，得到一些吹气位置和吹气量与侧向力之间的响应关系。 介绍了计算网格连续性、均匀性及正交性优化方法，对优化前后的网格进行了比较。并应用有限体积法对三维N-S方程进行离散，用二阶迎风格式对N-S方程进行求解，同时给出了对边界条件的处理方法。讨论了一些工业湍流模型的特点及应用范围，并对各自的计算结果进行对比分析，找到合适的计算模型。 利用数值模拟方法，对尖拱形细长旋成体大迎角非对称流场进行了分析，讨论了人为扰动、压缩性、迎角等流场因素对整个流场的影响，以及它们和模型侧向力之间的响应关系。同时讨论了大迎角旋成体背涡生成和发展情况，给出该状态非对称涡的结构模型。 利用细长旋成体背涡结构对尖头部扰动非常敏感的特性，采用在尖头部施加单孔位微吹气扰动的控制方法对细长旋成体侧向力进行控制，通过对吹气孔位置、吹气量与非对称流场之间响应关系的研究，该控制方法是可行的，同时得到了吹气孔周向有效位置以及一些状态下吹气量与侧向力之间的响应关系。 通过本文的研究，加深了对细长体大迎角非定常流场的认识，证明了单孔位微吹气扰动控制方法简便、有效，为以后继续深入研究打下了基础。更多还原

【Abstract】 Dynamic manipulation of forebody vortices as a means to obtain directional control of high-perfomance aircraft at high angles of attack is investigated. A tangent ogive shape of a slender body of the revolution is chosen as most representative of a real nose geometry of either a missile or military aircraft.In order to determine the characteristics of forebody flow asymmetry, a systematic study of lee-ward flow field over a slender body of the revolution on the high-angle-of-attack is conducted now.Effects of continuum, smooth, boundary-fitted and orthogonal grids on numerical results are discussed. And the generational method of 2-D grids is elucidated. The three dimensional Navier-Stokes equations are discretized using finite volume method, and time marching method is upwind scheme. The managements of boundary conditions and some industrial turbulence models are discussed.With the numerical method, investigations of the behaviors of the flow over the slender cylindrical body on the high-angle-of-attack are conducted, and the effects of the manual disturbances, the Mach number and the angle of attack on the flow field are discussed. The asymmetric vortex structure of the slender cylindrical body growing gradually along the symmetry axis of the slender body is shown.The SHM(Single Hole Microblowing) as a new perturbation active control technique was applied to the slender body with different Reynolds numbers at high angle of attack. With the analyzing and contrasting the distribution of the surface pressure distributions and the section side forces,the results indicated that the control ability of SHM has strong adaptability to various slender body at high angles of attack,and its control ability is effected by the Reynolds numbers.The investigation of the flow field show that the SHM control technique make an efficient control of side-force for both laminar and turbulent flow separation around forebody, and contribute to the research in the future.更多还原