## 5 Conclusions  
In this study, a segmented line source model was developed for predicting the environmental noise distributions of high-speed Maglev trains by integrating uniform finite-length incoherent moving line source (UFL-IMLS) radiation theory with numerical simulations of the external flow field of a Shanghai Maglev train. The key findings are as follows:  
1. Flow Field Analysis: Incorporating air compressibility effects, the LES method was employed to conduct numerical simulations of the external flow field surrounding a Shanghai Maglev train. The analysis revealed distinct three-dimensional vortical structure distributions with regions of elevated vorticity magnitude concentrated at the vehicle surface and wake zone. Flow separation was observed at the streamlined shoulder of the trailing car, whereas the wake region exhibited a complex array of multiscale vortices with varying intensities, dominated by a pair of counter-rotating ribbon-like trailing vortices. The vortex was the main sound source of fluid flow, and the noise energy was mainly concentrated in the turbulent movement area, such as near the surface of the vehicle body and the wake area. Therefore, the five parts of the turbulent movement around the train were taken as the five-segment line sources. 2. Model Validation: The results of a five-segment UFL-IMLS equivalent model derived from the flow simulation data demonstrated strong agreement with the on-site mea  
Figure 16: Measured and predicted equivalent continuous A-weighted SPLs as a function of the lateral distance from the guideway centerline (1.2 m above the ground). surements. The maximum absolute deviations in the equivalent sound levels across the monitoring points were constrained to 1.3 dB(A), satisfying the requirements of engineering predictions. 3. High-Speed Extrapolation: The validated predictions were extended to 600 km/h operation, generating lateral attenuation curves of equivalent continuous A-weighted SPLs and time-domain profiles and providing critical reference information for ultra-high-speed Maglev noise assessment. The time-domain curves of each velocity had similar trends, and the time-domain curve peaks became sharper with an increase in velocity. The curve trends of equivalent continuous A-weighted SPLs with the lateral distance were the same at each speed, and at 600 km/h, the equivalent continuous A-weighted SPLs decreased by 11.8 dB as the logarithm of the lateral distance doubles. Conceptualization, S.C.; methodology, S.C.; software, S.C., L.J. and Y.C. ; validation, S.C.; formal analysis, L.J. ; investigation, L.J. ; resources, J.G. ; data curation, S.C.; writing the original draft, S.C.; writing, review, and editing, S.C. and J.G. ; visualization, S.C. and Y.C. ; supervision, J.G. ; project administration, J.G. ; funding acquisition, J.G. All authors have read and agreed to the published version of the manuscript. This research was funded by the Major Strategic Projects of The Chinese Academy of Engineering [grant number: 2018-ZD-16] and CRRC Academy [grant number: 2022 CYY004]. The raw data supporting the conclusions of this article will be made available by the authors on request. We gratefully acknowledge [PERSON] (Appraisal Center for Environment & Engineering, Ministry of Ecology and Environment, Beijing) for assistance in securing funding through the Major Strategic Projects of the Chinese Academy of Engineering [grant number: 2018-ZD-16] and [PERSON] and [PERSON] (CRRC Qingdao Sifang Rolling Stock Research Institute, Qingdao) for their contributions to funding acquisition via the CRRC Academy [grant number: 2022 CYY004]. Author [PERSON] was employed by the company CRRC Zhuzhou Times New Material Technology Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.