高超声速圆球绕流流场及其近尾尾迹流场电磁散射特性分析  

Analysis of the Scattering Characteristic for the Hypersonic Flow Field with Near Wake Region of Sphere

作　　者：常雨[1] 陈伟芳[2] 吴其芬[1] 

机构地区：[1]国防科技大学航天与材料工程学院,湖南长沙410073 [2]浙江大学航空航天学院,浙江杭州310027

出　　处：《国防科技大学学报》2009年第1期5-10,共6页Journal of National University of Defense Technology

基　　金：国家部委基金项目

摘　　要：采用分段线性电流密度递归卷积时域有限差分(PLJERC-FDTD)方法计算高超声速导电金属球绕流流场及其近尾尾迹流场电磁散射特性,分析等离子体绕流流场RCS的频率特性、双站散射特性、极化特性及随飞行高度、飞行马赫数、入射角的变化关系。计算表明,前向散射方向是全方位散射中RCS取得最大值的方向;马赫数较大(本文Ma≥14)时,入射波频率增大、马赫数增大及飞行高度降低,绕流流场前向RCS增大。马赫数较小(本文Ma≤10)时,飞行马赫数、高度及入射角变化对绕流流场UHF、L、S波段后向RCS和双站RCS影响很小;在UHF、L波段,绕流流场及本体的后向RCS差距较小。马赫数较大时,大范围过密等离子体尾迹的形成使得电磁波垂直轴线入射时绕流流场增大了目标本体的后向RCS;在L、S波段,绕流流场后向RCS曲线可用一条直线逼近。A piecewise linear JE recursive convolution finite-dlfference time-domain （PLJERC-FDTD） algorithm is applied to the study of the scattering characteristics of the hypersonic flow field with near wake region of conductive metal sphere. Yhe effects of incidence wave frequency, incidence angle, scattering angle, polarization angle, altitude and Math number on the radar cross section （RCS） are analyzed. The results illustrate that the forward RCS is the maximal RCS of all scattering orientations＇ RCS. The forward RCS increases with the rise of incidence wave frequency and Maeh number, decreases with the decline of altitude when the Math number is not less than 14 in this article. The backward RCS and the bistatic RCS of flow fields vary very small with Math number, altitude and incidence angle for UHF, L and S band, the margin of the backward RCS between flow fields and sphere are small when the Mach number is not more than 10. The backward RCS of flow fields is more than the sphere＇ s because of the formation of wide over-dense plasma wake, the curve of backward RCS varies when the incidence wave frequency can be approached by one line for L, S band ff the incidence orientation is perpendicular to the X-axis and the Mach number is not less than 14.

关 键 词：时域有限差分 雷达散射截面 电磁波 等离子体 高超声速绕流 尾迹 

分 类 号：V221[航空宇航科学与技术—飞行器设计]