晴空状态下飞机尾流的雷达散射截面分析

Analysis of the Radar Cross Section of Aircraft Wake Vortex for Clear Air

假设飞机对大气扰动产生的尾流系统是熵恒定的,可认为尾流边界与周围大气没有冷热交换,由折射系数与大气参数的关系和理想气体状态方程得到了尾流大气的径向密度分布特性。结合湍流理论和流体力学中的举力线理论给出了一种计算尾流湍流RCS特性的计算方法,并分析得到飞机尾流的位折射系数、介电常数分布及雷达体反射率等重要特性参数,进而得到了尾流RCS随入射波频率变化及雷达距离变化的关系,这可为机场雷达实时探测和定位飞机尾流提供理论数据支持。

Hypothesis the entropy in the wake vortex system which created by airplane passes through the atmosphere is constant, and lack of heating or cooling of the rolling-up boundary layer. The radial density gradient distributing characteristic is gained by ideal gas state equation and the relationship between refractive index and atmosphere parameters. Combining the turbulence theory and the lifting line theory in hydrodynamics, a method which can calculate the RCS characteristic of wake vortex is presented. And we gained many important characteristic parameters such as the potential refractive index, the dielectric constant distribution, and the radar volume refractivity. Furthermore, we can obtain the relationship between wake vortex RCS with incidence wave frequency and radar rang when it changing. This can provide theory data for airdrome radar to detect and locate aircraft wake vortex.