Research on the mechanism of micro-pressure waves in a high-speed train passing through a high geo-temperature tunnel

In this study, tests and simulations are used to investigate the changes in micro-pressure waves (MPWs) generated by high-speed trains passing through high geo-temperature tunnels. First, moving model tests of highspeed trains passing through local high-temperature tunnels are conducted, and then the simulation results are compared with the experimental results to verify the accuracy of the numerical algorithm. The results show that high temperature reduce the pressure gradient and alleviate MPWs. When the length of the high-temperature zone in the tunnel is within the streamlined length of the train (12.5 m), MPWs decrease as this length increases. When the length exceeds the streamlined length, MPWs basically no longer change. When the length equals the streamlined length and the air temperature in the tunnel reaches approximately 323 K, MPWs are reduced by 9.1%. This paper also presents the influence of the circumferential angle of the tunnel high temperature zone on MPWs. MPWs gradually decrease with increasing heating angle when the angle is less than 225 and remain basically unchanged when the angle is greater than 225. The results provide a method for mitigating MPWs and guidance for scholars who study MPWs mechanism in high geo-temperature tunnels.