压缩波惯性作用对其波形演变的影响

为了准确地评估隧道出口微压波,基于一维平面波方程和压缩波的特性,推导了压缩波在隧道内传播时压缩波压力梯度的理论公式.采用该理论公式,分析了传播距离,初始压缩波幅值以及初始压缩波波前长度等因素对隧道不同位置处压缩波压力波梯度的影响.结果表明:压缩波压力梯度随着传播距离的增加而増大,其变化幅度越来越大,当传播距离接近临界长度时,其压力梯度几乎发生突变;相同的传播距离下,压缩波压力梯度随初始压缩波幅值的增加而增加,随初始压缩波波前长度的增加而减小;当传播距离小于临界长度时,理论公式和数值计算结果的相对误差小于6%,数值计算结果与文献报道的实测结果吻合良好. 

Influence of Inertial Effect of Compression Wave on Waveform Evolution

In order to accurately assess the micro-pressure wave outside tunnel exits, a theoretical formula of pressure gradient of wavefronts was deduced based on the one-dimensional plane wave equation and the flow characteristics of compression wave. The effects of propagation distance, and the amplitude and wavefront length of the initial compression wave on pressure gradient at different positions were analyzed using this theoretical formula. The results indicate that the pressure gradients significantly increase with propagation distance. When the propagation distance is close to the critical length, the pressure gradients show an abrupt change. With the same propagation distance, the pressure gradients increase along with the amplitude of the initial compression wave and decrease with the length of wavefront. When the propagation distance does not exceed the critical length, the relative error between the theoretical formula and numerical calculation is less than 6%, and the numerical results agrees well with measurements reported in literature.