Key Takeaways & Executive Findings
- •• Shaft parameters (location, cross-sectional dimension, height) significantly influence the initial compression wave amplitude and gradient, with linear and nonlinear relationships identified. • Optimized shaft configuration (W=8 m, L=50 m, h=20 m) substantially reduces compression wave amplitude and gradient. • Portal cross-sectional area of 210 m² achieves a 53.24% reduction in compression wave gradient, comparable to optimized openings (53.96%). • Micro-pressure waves exhibit a dual-peak structure; opening location enables selective peak regulation, with optimized parameters reducing initial compression wave gradient by over 50%.
Abstract
To address the severe aerodynamic effects caused by a 600 km/h superconducting maglev train passing through a tunnel at full speed, this study systematically investigates the coupled influence of auxiliary facility parameters including the shaft (location L, cross sectional dimension W, height h), tunnel portal (cross sectional area S), and openings (spacing D, side length F) on the evolution of tunnel aerodynamic effects. By integrating three dimensional unsteady flow field numerical simulations with a dynamic model testing system, the research notably reveals the regulatory mechanisms of these parameters on the evolution characteristics of the initial compression wave pressure gradient and the multi peak structure of micro-pressure waves. The results show that shaft parameters significantly affect the initial compression wave. Both the wave amplitude and gradient exhibit a linear negative correlation with cross sectional dimension W and a linear positive correlation with location L, while demonstrating a nonlinear relationship with height h, the amplitude follows a cubic polynomial trend, and the gradient initially increases before plateauing. Under the configuration W=8 m, L=50 m, and h=20 m, substantial reductions in both compression wave amplitude and gradient were achieved. The portal cross sectional area S shows a "U-shaped" relationship with the compression wave gradient, with the maximum gradient reduction of 53.24% occurring at S=210 m2, a result comparable to that achieved with optimized opening parameters (D=15 m, F=3.5 m, 53.96%). Regarding micro-pressure waves, the amplitude measured 20 m from the tunnel exit shows a linear positive correlation with shaft parameters L and W, while the influence of h saturates beyond 50 m. Reductions exceeding 54% were achieved with portal parameters, either at S=210 m2 or using the optimized opening configuration. Furthermore, micro-pressure waves near the portal exhibit a consistent dual peak structure: the first peak originates from the train entry compression wave, and the second results from further wave compression after tunnel exit. The opening location governs selective peak regulation openings near the portal entrance primarily suppress the first peak with minimal impact on the second, whereas centrally located openings reduce the first peak but can amplify the second by up to 3%. Based on these insights, an optimized parameter configuration is proposed: a shaft with a cross-sectional dimension ≥8 m located 50 m from the portal, a portal cross sectional area of 210 m2, and openings spaced at 15 m intervals. This configuration can reduce the initial compression wave gradient by over 50%. The results provide a theoretical foundation for controlling aerodynamic effects of superconducting maglev train.
1. Introduction
As rail transportation progresses toward higher speeds, the 600 km/h superconducting maglev train has become the focus of next-generation high-speed transportation technology due to its advantages such as contactless suspension and zero mechanical friction [1−3]. However, in the enclosed environment of a tunnel, when the superconducting maglev train passes through at full speed (600 km/h), it induces intense aerodynamic effects [4, 5]. The transient pressure wave amplitude can exceed 10 kPa, far surpassing the human ear membrane tolerance threshold (±1.5 kPa), seriously threatening passenger comfort and health. At the same time, the pulsating pressure waves repeatedly impact the tunnel walls, accelerating the fatigue damage process of the concrete structure [7, 8]. These aerodynamic hazards have become a key bottleneck restricting the tunnel operation of superconducting maglev systems.
In the train tunnel aerodynamic characteristic mitigation strategies, the characteristic parameters of shafts and tunnel portals play a fundamental role in regulation [9−11]. OKUBO et al [12] studied the impact of micro-pressure waves in tunnels with large branch shafts, showing a positive correlation between micro-pressure and train speed, and a negative correlation with the shaft cross-sectional area. ZHOU et al [13] used a moving model experimental device to investigate the effect of the location o...
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PAN Shen-gong, ZHANG Lei, WANG Tian-tian, YU Qing-song, LIN Tong-tong, XU Shu (2025). Effects of shaft and tunnel portal on coupled aerodynamic characteristics of 600 km/h superconducting maglev train. Journal of Central South University. https://doi.org/10.1007/s11771-025-6142-9
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Frequently Asked Questions
What is the main objective of this study?
The study systematically investigates the coupled influence of shaft and tunnel portal parameters on the aerodynamic effects of a 600 km/h superconducting maglev train passing through a tunnel, aiming to propose an optimized configuration to reduce pressure waves.
How do shaft parameters affect the initial compression wave?
Shaft cross-sectional dimension (W) shows a linear negative correlation with wave amplitude and gradient, while location (L) shows a linear positive correlation. Height (h) exhibits a nonlinear relationship: amplitude follows a cubic polynomial trend, and gradient initially increases before plateauing.
What is the optimal portal cross-sectional area for reducing compression wave gradient?
The optimal portal cross-sectional area is 210 m², which achieves a maximum gradient reduction of 53.24%, comparable to the reduction achieved with optimized opening parameters (53.96%).
What is the dual-peak structure of micro-pressure waves near the portal?
Micro-pressure waves near the portal exhibit a consistent dual-peak structure: the first peak originates from the train entry compression wave, and the second results from further wave compression after tunnel exit. Opening location can selectively regulate these peaks.
What is the proposed optimized parameter configuration?
The proposed configuration includes a shaft with cross-sectional dimension ≥8 m located 50 m from the portal, a portal cross-sectional area of 210 m², and openings spaced at 15 m intervals. This configuration can reduce the initial compression wave gradient by over 50%.
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