Detached-Eddy Simulation of Ground Effect on the Wake of a High-Speed Train

Xia, Chao; Shan, Xizhuang; Yang, Zhigang

doi:10.1115/1.4035804

Cited by 22 publications

(2 citation statements)

References 29 publications

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“…It is found that the CFL number remains below one, with only a small number of localized exceptions occurring. Previous studies have shown that this minor infringement on the stringent CFL requirement has no significant effect on the simulations [76][77][78]. The quality of the mesh has been checked by other quantities as well, such as the blending function and the turbulent viscosity ratio, which also confirm that the present mesh meets the requirement of the IDDES model [39].…”

Section: Mesh Independence and Numerical Validationsupporting

confidence: 72%

Numerical Investigation of The Aerodynamics of Lorry Platooning Travelling through Road Tunnels

Zhang

Soper²,

Fraga³

et al. 2023

Univers. J. Civ. Eng.

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With potential benefits in drag reduction and fuel saving, the aerodynamics of vehicle platoons have been investigated for a wide range of cases in open space. When vehicle platoons travel in road tunnels, the platooning strategy could be affected by the tunnel size, the traffic lane, and the inter-vehicle spacing. This paper presents a detailed investigation of these effects by numerically simulating the aerodynamics of an eight-lorry platoon travelling through road tunnels. The slipstream velocity and pressure fields, flow structures, and drag forces are examined as the inter-vehicle spacing are varied from 0.1L to 1.5L, where L is the length of a single lorry. It is found that the airflow induced by the moving platoon in the large tunnel (two-lane tunnel) is weaker than that in the small tunnel (single-lane tunnel), but similar to the case in the open air. As a result, the drag reduction due to platooning is most significant in the small tunnel, while the results in the large tunnel and the open air are largely identical. It is further found that, owing to the efficient shielding, the drag reduction in the open air increases monotonically as the inter-vehicle spacing decreases. However, the flow fields in both small and large tunnels change pronouncedly when the inter-vehicle spacing is 0.25L, resulting in relatively larger drag coefficients at this spacing. These findings are less sensitive to the traffic lane. This study provides useful insight into the platooning strategy of a long lorry platoon.

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Section: Mesh Independence and Numerical Validationsupporting

confidence: 72%

Numerical Investigation of The Aerodynamics of Lorry Platooning Travelling through Road Tunnels

Zhang

Soper²,

Fraga³

et al. 2023

Univers. J. Civ. Eng.

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“…Bell et al 13,14 found that the flow field in the lower part of the train under flat ground condition differed significantly compared to embankment ground condition. Xia et al 15 found that the lateral force and lift force of the train fluctuated considerably, and the vortex pair shedding frequency was higher under the fixed ground through an IDDES simulation. Wang et al 16 used IDDES to investigate the effect of ground relative motion on slipstream under three different ground/wheel configurations.…”

Section: Introductionmentioning

confidence: 99%

Noise contribution and coherence analysis of high-speed train head shape under moving slab track

Zhuo-ming

Yang

2022

Proceedings of the Institution of Mechanical Engineers, Part F:

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Aerodynamic noise generated by 1:8 scale three carriages high-speed train was investigated by numerical simulation and wind tunnel test. The difference of far-field noise below 1600 Hz between simulation based on dense mesh and test is less than 3 dB(A), which indicates that the current simulation method has reasonable accuracy. It is found that dipole source can be used as the only sound source to calculate the far-field noise because its intensity is more significant than that of the quadrupole source. The subdomain method is applied to investigate the noise contribution and coherence analysis of full-scale head shape. It is found that the far-field noise contributions of the frame, bogie cavity and wheel set are significant, and the peak frequency occurs at the frequency of 630 Hz. Coherence analysis indicates that the far-field noise with the train body as the sound source has a relatively high correlation with the pressure pulsation caused by the vortex structure generated at the wiper housing and the bogie. Also, the side vortex near the front wheel has a higher correlation with the far-field noise at a higher frequency, while a stronger correlation between that near the rear wheel and the far-field noise occurs at a lower frequency.

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