摘要
研究大气湍流对声爆的影响对于新一代超声速民机的低声爆设计具有重要意义。在真实大气环境中,大气湍流是普遍存在的,其会使低声爆波形在由高空向地面传播的过程中发生扭曲、畸变和振荡,并改变波形的能量分布。利用基于单向近似假设的二维HOWARD方程,以类Tu-144飞机的N型波和经过JSGD声爆最小化理论设计的低声爆波形为对象,研究分层大气湍流对N型波和低声爆波形的影响。首先,介绍了考虑大气边界层湍流效应的声爆传播模拟方法,包括改进的二维HOWARD方程及其离散求解方法、分层大气湍流场的建模方法,并采用JAXA抛体试验数据对预测方法的有效性进行了验证,同时与KZK方程预测结果进行了对比。其次,运用本文发展方法研究了N型波和低声爆波形在分层大气边界层湍流场中的传播情况,对地面可观测波形的主观噪声级和超压峰值进行了统计分析,发现大气湍流对增大N型波和低声爆波形主观噪声级(ASEL、PLdB)的概率很小,但很大程度上会增强波形超压峰值。最后,通过改变大气湍流生成过程中3个参数的数值,研究了不同强度的大气湍流场对声爆波形的影响,结果表明:风速脉动幅值和湍流积分尺度的增强对N型波和低声爆波形的感觉声压级影响较大,其平均值随湍流强度的增强而减小,但最大值却增大。因此,对于超声速民机低声爆设计来讲,仍然需要确定大气湍流对地面声爆的影响程度,评估湍流场作用下波形偏离设计结果的可能性。
It is of significance to study the effect of atmospheric turbulence on sonic boom for the design of nextgeneration low-boom supersonic commercial aircraft.The atmosphere turbulence in the real world will distort the waveform and change the sound energy distribution on the spectrum domain,when the sonic boom is propagated from the cruising altitude to the ground.In this paper,a modified Heterogeneous One-Way Approximation for the Resolution of Diffraction(HOWARD)equation is developed to study the effects of the stratified atmosphere turbulence on sonic boom waveforms,taking the N-type wave of a Tu-144-like aircraft and the low-boom waveform designed based on the JSGD sonic boom minimization theory as examples.First,a method for simulating sonic boom propagation through the atmospheric boundary layer is introduced,which includes the modified HOWARD equation together with the numerical solving strategy and the modeling method for stratified atmospheric turbulence.The above method is validated by comparing the predictions with the flight test data of LBM and NWM in the JAXA D-SEND project.Comparisons of predictions by the above method and the KZK equation are also carried out.Second,the method proposed is applied to investigate the propagation of N-type and low-boom waves through an atmospheric turbulence.The statistics of noises and the peak overpressure for the observable waveforms on the ground show that the probability of increasing noises(ASEL and PLdB)due to atmosphere turbulence is lower,but peak overpressure is highly possible to increase due to atmosphere turbulence.Finally,the method is also applied to study the effect of intensity of atmosphere turbulence on sonic boom by changing three parameters for generating turbulence.The enhancement of atmosphere turbulence described by the wind fluctuation and the integral scale has great influence on the perceived level of the N-type and low-boom waves.With the increase of turbulence intensity,the average values of the decibel become lower,while the maximum values of the decibel become greater.Therefore,it is necessary to evaluate effects of atmosphere turbulence on sonic boom in the design of low-boom supersonic commercial aircraft.
作者
乔建领
韩忠华
丁玉临
宋文萍
宋笔锋
QIAO Jianling;HAN Zhonghua;DING Yulin;SONG Wenping;SONG Bifeng(Research Center for Environment-friendly Supersonic Civil Transports(ReCESST)/Institute of Aerodynamic and Multidisciplinary Design Optimization,School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,China;National Key Laboratory of Science and Technology on Aerodynamic Design and Research,School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,China)
出处
《航空学报》
EI
CAS
CSCD
北大核心
2023年第2期120-135,共16页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(12072285)
陕西省自然科学基金(2020JM-127)
陕西省杰出青年基金(2020JC-13)。
关键词
声爆
超声速民机
HOWARD方程
大气湍流
计算流体力学
sonic boom
supersonic commercial aircraft
HOWARD equation
atmospheric turbulence
computational fluid dynamics
