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基于广义Burgers方程的声爆传播特性大气湍流影响研究-超声速民机气动专栏

王迪1,2,冷岩3,杨龙3,韩忠华2,钱战森3   

  1. 1. 航空工业空气动力研究院
    2. 西北工业大学
    3. 中国航空工业空气动力研究院
  • 收稿日期:2021-09-03 修回日期:2021-10-10 出版日期:2021-10-12 发布日期:2021-10-12
  • 通讯作者: 钱战森
  • 基金资助:
    国家自然科学基金

Atmospheric turbulence effects on sonic boom propagation based on augmented Burgers equation

  • Received:2021-09-03 Revised:2021-10-10 Online:2021-10-12 Published:2021-10-12
  • Contact: Zhansen Qian

摘要: 声爆是发展超声速民机亟需突破的关键瓶颈问题之一。目前流行的声爆预测技术主要针对静止大气,对大气中的湍流扰动等动态效应考虑不足,尚未建立高效高逼真度的预测方法。前期的研究基于波形参数法框架,通过在射线法中引入由Von Karman能量谱和离散Fourier模态有限和生成的均匀各向同性湍流速度场,考虑了大气湍流的部分效应,但是对热黏性吸收、分子弛豫等大气物理效应没有同时模拟,然而实际飞行中大气湍流和热黏性吸收、分子弛豫等大气物理效应是同时影响声爆特性的,进而会影响超声速民机的轨迹规划。该项工作基于广义Burgers方程的远场声爆预测方法,通过与射线法相结合,建立了一套可考虑热黏性吸收、分子弛豫等物理效应的大气湍流声爆影响快速预测方法,并采用该方法开展了大气湍流强度和大气边界层厚度对典型远程超声速民机的声爆特性影响规律研究。计算结果表明:本文建立的预测方法能够合理表征热黏性吸收、分子弛豫等大气物理效应,相比前期基于波形参数法框架的预测方法,能够更加真实地反映大气湍流对声爆传播特性的影响;相比于前期的典型超声速公务机,本文采用的远程超声速民机声爆波形更加复杂,该预测方法仍能给出复杂波系的大气湍流影响规律;随着湍流强度和边界层厚度的增加,大气湍流效应对声爆特性产生的随机性影响呈增强趋势;同时,声爆在地面到达点的位置也呈现出更加分散的趋势,其可能会改变声爆毯对地面的影响范围,应在飞行轨迹规划中予以考虑。

关键词: 超声速民机, 均匀各向同性大气湍流, 广义Burgers方程, 声爆预测, 湍流强度, 大气边界层

Abstract: Sonic boom is one of the key issue that urgently need to be solved for the development of supersonic civil aircraft in the future. The current popular sonic boom prediction technology is mainly for the static atmosphere, which does not consider the dynamic effects such as turbulence disturbance in the atmosphere, and no efficient and high-fidelity prediction method has been established. The previous research was based on the framework of the waveform parameter method. By adding the random velocity field of homogeneous isotropic atmospheric turbulence in the ray tracing method which is calculated from the Von Karman energy spectrum and the finite sum of discrete Fourier modes, the partial effects of atmospheric turbulence were considered. However, the physical effects of the atmosphere such as thermoviscous absorption and molecular relaxation have not been simulated, which could also affect the sonic boom in actual flight, and then affect the trajectory planning of supersonic civil aircraft. This work is based on a far-field sonic boom prediction by solving the augmented Burgers equation, after combining with the ray tracing method, a set of rapid sonic boom prediction methods that considering the physical effects of thermoviscous absorption and molecular relaxation are established. Afterwards, this method is used to study the influence of atmospheric turbulence intensity and atmospheric turbulence boundary layer height on the sonic boom signatures of a typical long-range supersonic civil aircraft. The results show that the prediction method established in this paper can reasonably characterize the thermoviscous absorption and molecular relaxation. Compared with the previous prediction method based on the waveform parameter method framework, it can truly describe the influence of atmospheric turbulence on the propagation characteristics of sonic boom. Furthermore, compared with the previous typical supersonic business jets, the sonic boom waveform of the example used in this article are more complicated, and this prediction method can still explain the influence of atmospheric turbulence in the complex wave system. Eventually, as the intensity of turbulence and the height of the boundary layer increase, the random influence of atmospheric turbulence on the characteristics of the sonic boom increase. At the same time, the location of sonic boom arrival points also shows a more scattered trend, which may change the impact range of the sonic boom on the ground. Therefore, the turbulence intensity and turbulence boundary layer height should be considered in flight trajectory planning.

Key words: supersonic civil aircraft, random homogeneous isotropic turbulence, augmented Burgers equation, sonic boom prediction, turbulence intensity, atmospheric boundary layer

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