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基于小波分析的爆轰波扰动响应特征研究

Study on the Response Characteristics of Detonation Wave Disturbances Based on Wavelet Analysis

  • 摘要: 本文基于高精度激光测风雷达对在北京香山和正阳门开展的两次爆轰动力扰动响应特征实验进行观测研究,并用小波分析方法考察爆轰扰动自然风场响应的动力学特征。结果显示:爆轰对风向影响明显,两次实验(<300m)均出现与爆轰开始、结束同步的风向转向现象。爆轰动力扰动产生雷诺应力效应,形成次级环流涡旋,其影响特征通过小波分析的优势振荡体现,爆轰激起了涡旋的多尺度结构,位于高度150-250m,并随高度升高衰减。两次实验爆轰动力扰动的影响均为垂直风向最强,形成的涡旋最大且稳定(尺度大、振幅大、周期长,随高度变化小);水平风向次之,随着高度升高低层大涡旋迅速转为高层小涡旋;水平风速最弱,形成涡旋小且弱(振幅小、周期短)。爆轰力度及其形式对动力扰动特征有明显影响,礼炮力度小、发射较发散,形成的次级流场较弱,对涡旋的维持和补充作用弱。以上表明非均匀的扰动气流场能够激发出非对称的涡旋对,而涡旋对的出现会引起优势风向的转变,并伴有运动尺度组分的变化,形成上升气流,打破原有平衡,可能使降水条件更有利,从而达到人工影响天气的效果。

     

    Abstract: This study delves into the two detonation experiments conducted in Xiangshan and Zhengyangmen, Beijing. Using high-precision laser wind radar and wavelet analysis, we explored the dynamic characteristics of the disturbance response of natural wind fields caused by shelling. The results show that detonation influences the wind field, with both experiments (below 300 m altitude) displaying a synchronous wind-direction turning phenomenon with the start and end of detonation. The dynamic disturbance caused by detonation generated a Reynolds stress effect and formed secondary circulation vortices. The impact of this disturbance is reflected by the dominant oscillation in wavelet analysis. Detonation stimulated the formation of multiscale vortex structures, predominantly located at heights of 150–250 m, which diminished with increasing altitude. Our analysis indicates that the impact of the dynamic disturbance in both experiments was the strongest in the vertical wind direction, resulting in the formation of large, stable vortices characterized by significant scale, amplitude, and duration, showing minimal variation with height. The horizontal wind direction was affected to a lesser extent, with larger vortices at lower altitudes quickly transitioning into smaller ones at higher altitudes. Conversely, the horizontal wind speed experienced the least impact, forming the smallest and weakest vortices with short periods and low amplitudes. The intensity and type of shelling significantly influenced the characteristics of wind-field disturbances. For instance, smaller salutes and more divergent launches resulted in weaker secondary flow fields, diminishing the maintenance and enhancement effect of shelling on the vortices. Our findings indicate that nonuniform disturbed airflow fields can excite asymmetric vortex pairs. The occurrence of these vortex pairs alters the dominant wind direction and wind components, thereby forming updrafts, disrupting the original balance, and possibly making conditions more favorable for precipitation, ultimately achieving artificial weather modification.

     

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