Key Takeaways & Executive Findings
- •• Noise barriers increase sound source intensity by 2.1–2.8 dB(A) for 400 km/h trains, with height-dependent effects varying along the train. • Thicker boundary layers near rear-middle and tail cars amplify crash wall influence, causing asymmetry and higher sound source intensity. • Higher barriers exacerbate flow asymmetry and sound source intensity due to deceleration/acceleration regions near the crash wall and barrier contraction. • DDES and FW-H coupling effectively captures barrier-induced aerodynamic noise mechanisms, aiding noise control design for high-speed rail.
Abstract
This paper aims to explore the influence of different noise barrier heights on the sound source generation mechanisms of higher-speed trains (400 km/h) using a combination of delayed detached eddy simulation (DDES) and Ffowcs Williams-Hawkings (FW-H) equations. Four cases are investigated and compared, i.e. 1) no barrier, 2) 2.3 m, 3) 3.3 m, and 4) 4.3 m single-side barriers on a bridge. Numerical results show that the presence of noise barriers causes an increase in sound source intensity ranging from 2.1 to 2.8 dB(A). However, the relationship between the barrier height and the increase in sound source intensity varies across different parts of the train. Compared with the head and front-middle cars, the boundary layer is thicker around the rear-middle and tail car areas. A thick boundary layer introduces the influence of the crash wall, causing asymmetry and increases in sound source intensity. This is due to the deceleration region formed between the crash wall and the rail surface, as well as the acceleration region formed by the contraction of the flow channel in the noise barrier, both of which influence the sound source's characteristics. In addition, higher barriers exacerbate asymmetry and increases in sound source intensity.
1. Introduction
The level of development of high-speed trains is an important indicator of a country's industrial capabilities [1−3]. Noise levels are one of the most important criteria for the future development of high-speed trains [4, 5]. Many studies have shown that high-speed railway noise is a composite noise made up of various types of noise mechanisms, such as traction noise, wheel-rail noise, and aerodynamic noise [6]. When the train's speed exceeds 350 km/h, aerodynamic noise becomes the primary noise source [7]. As a result, researchers have always focused their attention on the mechanism of aerodynamic noise generation in the key sound source region of high-speed trains, as well as the corresponding control measures.
Until now, researchers have conducted numerous on-site measurements [8], wind tunnel tests [9−11], and numerical simulations [12] to investigate the noise characteristics of high-speed trains, as well as the generation mechanism. It is found that the aerodynamic noise of high-speed trains is primarily broadband noise, with sound energy distributed mainly in the low and mid frequency bands. The main aerodynamic noise source components include the bogie area, the pantograph area, the carriages connected to the windscreen, and the head car and tail car streamline position [13, 14]. Noise generation mechanisms differ between areas. The noise generation mechanism in the bogie area is primarily due to the interaction of the flow structure generated by the high-speed aerodynamic flow through the bogie cabin and the flow structure generated by the wheels, axles, and other blunt bodies in a narrow space, which is part of the coupled noise of cavities and blunt bodies in the near-ground space [15]. Although the pantograph area can also be simplified as a combination of cavity and blunt body, the noise generation mechanism is different. Specifically, the length-to-depth ratio of the bogie cabin is generally 4−6, which belongs to the open cavity, and the noise intensity of cavity flow around it is stronger. The length-to-depth ratio of the pantograph pit is frequently 10−14, and without considering the flow interference of the pantograph and other blunt parts, the pantograph pit belongs to the transition-closed cavity, and the noise intensity of the noise generated by the cavity flowing around it is weaker [16, 17]. As a result, the noise in the pantograph region is primarily concentrated in the blunt body parts, such as the bow head, hinge, and base, and it is caused by flow separation, vortex shedding, and flow interactions between the blunt bodies [18]. When the cabin connecting windsc
Loading authentic research manuscript (Pages 1–5)...
LU Wei-shuang, HUANG Jun-hui, SUN Zhen-xu, PRASERT Prapamonthon, GUO Di-long, YANG Guo-wei, SONG Zhe-nan, HU Wen-lin (2025). Effect of height of noise barriers on sound source characteristics of aerodynamic noise from high-speed trains. Journal of Central South University. https://doi.org/10.1007/s11771-025-6144-7
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the effect of noise barrier height on aerodynamic noise from high-speed trains?
The study found that noise barriers increase sound source intensity by 2.1–2.8 dB(A) for trains at 400 km/h. The increase varies with barrier height and train location, with higher barriers exacerbating asymmetry and sound source intensity, especially near rear-middle and tail cars.
How does the presence of noise barriers affect sound source characteristics?
Noise barriers alter the flow field, creating deceleration and acceleration regions that influence sound source generation. They cause an increase in sound source intensity and asymmetry, particularly where boundary layers are thicker, such as near the crash wall.
What numerical methods were used in this study?
The study used delayed detached eddy simulation (DDES) coupled with Ffowcs Williams-Hawkings (FW-H) equations to simulate and analyze the aerodynamic noise generation mechanisms.
Why does the sound source intensity increase with barrier height?
Higher barriers intensify flow contraction and acceleration, as well as the deceleration region near the crash wall, leading to stronger flow fluctuations and thus higher sound source intensity.
What are the practical implications of this research?
The findings provide insights for optimizing noise barrier design to mitigate aerodynamic noise from high-speed trains, considering the trade-off between barrier height and noise reduction effectiveness.
Related Technical Papers & Translations
Direct Repair of the Crystal Structure and Coating Surface of Spent LiFePO4 Materials Enables Superfast Li-Ion Migration
The rapid accumulation of spent LiFePO4 (LFP) cathodes from retired lithium-ion batteries necessitates the development of effective and environmental-friendly recycling strategies. In this context, direct regeneration has emerged as a promising approach for reclaiming LFP cathode materials, offering a streamlined pathway to restore their electrochemical functionality. We report an integrated regeneration protocol that simultaneously repairs the degraded crystal structure and reconstructs the damaged carbon coating in spent LFP. The regenerated cathode material had superfast lithium-ion diffusion kinetics and a stable cathode–electrolyte interface, giving a remarkable rate capability with specific capacities of 122 mAh g−1 at 5C and 106 mAh g−1 at 10C (1C = 170 mA g−1). It also maintained capacities of 110.7 mAh g−1 (5C) and 84.1 mAh g−1 (10C) after 400 cycles. It could be used in harsh environments and could be stably cycled at subzero temperatures (−10 and −20 °C) and in solid-state electrolyte batteries. Life cycle assessment combined with economic evaluation using the EverBatt model reveals that this direct regeneration approach has high economic and environmental benefits.
Oxide Semiconductor for Advanced Memory Architectures: Atomic Layer Deposition, Key Requirement and Challenges
Oxide semiconductors (OSs), introduced by the Hosono group in the early 2000s, have evolved from display backplane materials to promising candidates for advanced memory and logic devices. The exceptionally low leakage current of OSs and compatibility with three-dimensional (3D) architectures have recently sparked renewed interest in their use in semiconductor applications. This review begins by exploring the unique material properties of OSs, which fundamentally originate from their distinct electronic band structure. Subsequently, we focus on atomic layer deposition (ALD), a core technique for growing excellent OS films, covering both basic and advanced processes compatible with 3D scaling. The basic surface reaction mechanisms—adsorption and reaction—and their roles in film growth are introduced. Furthermore, material design strategies, such as cation selection, crystallinity control, anion doping, and heterostructure engineering, are discussed. We also highlight challenges in memory applications, including contact resistance, hydrogen instability, and lack of p-type materials, and discuss the feasibility of ALD-grown OSs as potential solutions. Lastly, we provide an outlook on the role of ALD-grown OSs in memory technologies. This review bridges material fundamentals and device-level requirements, offering a comprehensive perspective on the potential of ALD-driven OSs for next-generation semiconductor memory devices.
Laser powder bed fusion of biodegradable Zn-4Cu alloy: Processing, microstructure and properties
Zn's natural degradability and biocompatibility make it a promising candidate for implants, however, its mechanical properties remain insufficient for bone applications. In this study, the performance of Zn was enhanced by developing Zn-Cu alloys via laser powder bed fusion (LPBF). Optimal LPBF parameters for forming stable tracks were achieved by adjusting laser power and scanning speed. Under optimized conditions of 100 W and 100 mm/s, high-density (99.58%) Zn-Cu alloys with improved hardness (68.2HV) and yield strength (160 MPa) were achieved. These improvements are attributed to solid solution strengthening, segregation strengthening, and grain refinement. The Zn-Cu alloys also demonstrated favorable degradation behavior, with a rate of 0.16 mm/year. This degradation is primarily driven by micro-galvanic corrosion between the CuZn5 phase and Zn matrix, along with refined grains and increased grain boundary density. This work demonstrates a viable strategy for fabricating Zn-based implants with enhanced structural integrity and mechanical performance via LPBF.