Study of Aerodynamic Noise induced by Shock Waves in Supersonic Flows and Development of a Method for Reducing the Noise

1.为实现铁路隧道模拟器，研制了一种快速开启闸阀。利用超高速摄像机对快开闸阀的性能进行了分析。结果表明，随着执行腔初始压力的增大，闸阀的开启时间缩短。明确了驱动腔初始压力与最大压力梯度等压缩波特性之间的关系。为了研究道碴对压力波在高速铁路隧道中传播变形的影响，利用快开闸阀制作了高速铁路隧道模拟器。对具有不同多孔材料壁面的模型隧道中传播的压缩波的变形进行了实验研究。实验数据表明，本文提出的缓解方法是可行的，并且多孔材料壁面的影响是明显的。采用二阶对称TVD方法格式，同时考虑了平壁上的流体摩擦和有碴轨道的影响，对压缩波形进行了数值研究。用双层法计算得到的隧道内压缩波波形与两条轨道隧道的现场试验数据吻合较好，说明本文的数值计算方法是合理的。

1. To accomplish the railway tunnel simulator, a fast opening gate valve was developed. we analyzed the performance of the fast opening gate valve by using a super high-speed video camera. The results show that the opening time of the gate valve decreases when the initial pressure in the actuating chamber increases. And the relation between the initial pressure in the actuating chamber and the characteristics of the compression wave such as the maximum pressure gradient was made clear.2. To study the ballast effect on distortion of pressure wave propagating in high-speed railway tunnel, we made a high-speed railway tunnel simulator using a fast opening gate valve. An experimental investigation was carried out to clarify the distortion of a propagating compression wave in a model tunnel with various porous material wall. Experimental data shows the possibility of the present alleviative method, and the effects of the porous material wall is clear.3. The compression waveform in the propagating process are studied numerically by second-order symmetric TVD method scheme, taking both fluid friction on the flat wall and the effect of the ballasted track into consideration. The waveform of the compression wave in the tunnel calculated by the present two-layer method is in good agreement with that of the field test data on both track tunnels, so that the present numerical method of calculation seems to be reasonable.