The optimum model determination of porous barriers in high-speed tracks

Mohebbi, Masoud; Safaee, Amir Mohsen

doi:10.1177/0954409721995323

Cited by 22 publications

(3 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, the numerical results were compared with the related experimental data. From 2021 to 2023, Mohebbi and Safaee [26]; Mohebbi and Rezvani [27]; and Mohebbi et al [28,29] in a series of parallel researches, performed influences of fences on the aerodynamic behaviors of a high-speed train using the Lattice Boltzmann Method. In the following, the porous wind barriers that are widely used in this industry have been investigated and compared.…”

Section: Introductionmentioning

confidence: 99%

Interaction Simulation of a Lateral Wall Distance on Aerodynamic Characteristics of a Simplified High-speed Train

Hajipour,

Mirabdolah Lavasani,

Eftekhari Yazdi

2024

Period. Polytech. Mech. Eng.

View full text Add to dashboard Cite

The natural features, such as mountain slopes, cliffs, and the human-made artificial walls, such as train station walls, windbreakers, and even residential and office buildings, can affect the movement structure of high-speed trains. In the present paper, using computational fluid dynamics (CFD), the interaction of lateral wall distances on the aerodynamic characteristics of a high-speed train is simulated. To achieve this -using OpenFOAM- the governing equations are solved. Also, the used solver is simpleFoam which the Simple algorithm (Semi-Implicit Method for Pressure Linked Equations) is applied to decouple the Navier-Stokes's equations. In the following a simplified high-speed train is considered, combining Reynolds-Averaged Navier-Stokes (RANS) equations and k-ω (SST) turbulence approach, an incompressible turbulent air-flow around it is simulated. Also, the flow and aerodynamic structures affected by distance changes between the lateral wall and the train are analyzed. Therefore, the lift, drag, and side aerodynamic forces and their corresponding moments as pitching, yawing, and rolling are provided and compared for four distance cases. In the following, the most significant components of flow structure, such as streamlines, velocity and pressure distributions, and vortices structures, are discussed. Finally, using the turbulent kinetic energy analysis, the air-flow's turbulent level around the train, especially in critical areas, is investigated. The findings illustrated that the closer distance between the train and the wall has more destructive effects on the movement of the high-speed trains. The results of the present study can be helpful for designing structures along the rail and distancing it from natural features.

show abstract

Section: Introductionmentioning

confidence: 99%

Interaction Simulation of a Lateral Wall Distance on Aerodynamic Characteristics of a Simplified High-speed Train

Hajipour,

Mirabdolah Lavasani,

Eftekhari Yazdi

2024

Period. Polytech. Mech. Eng.

View full text Add to dashboard Cite

show abstract

“…Computational fluid dynamics (CFD) is an important method to understand the aerodynamic behaviour of HSRTs (Chen et al , 2019; Chen et al , 2021, 2022a, 2022b; Cuhadaroglu, 2009; Dang et al , 2015; Ma et al , 2018b, 2019, 2021; Kulak et al , 2018; Yang et al , 2018). For example, Mohebbi and Rezvani (2018, 2021) used CFD simulation to investigate the aerodynamic performance of trains when running in wind barriers and tried to optimum the porous barrier design considering the running safety of the train (Mohebbi and Safaee, 2022). Yang et al (2018) simulated the process of an HSRT entering a tunnel and found that the flow and pressure structure near the train undergoes a transient variation, which causes a pulse swing movement and a sudden fluctuation in aerodynamic loads.…”

Section: Introductionmentioning

confidence: 99%

Field test and numerical reconstitution of natural winds at the tunnel entrance section of high-speed railway

Yang

Liu

Deng

et al. 2022

HFF

View full text Add to dashboard Cite

Purpose The purpose of this paper is to understand the natural wind field characteristics of the tunnel entrance section and analyzing the aerodynamic performance of high-speed railway trains (HSRTs) under natural winds. Design/methodology/approach Three typical tunnel entrance section sites, namely, tunnel–bridge in a dry canyon (TBDC), tunnel–bridge in a river canyon (TBRC) and tunnel–flat ground (TF), are selected to conduct a continuous wind field measurement. Based on the measured wind characteristics, the natural winds of the TBDC and TF sites are reconstituted and imported into the two corresponding full-scale computational fluid dynamics models. The aerodynamic loads of the HSRT running on TBDC and TF with reconstituted winds are simply analyzed. Findings The von Kármán spectrum can be used to describe the wind field at the tunnel entrance section. In the reconstituted natural wind condition, a time-varying feature of wind speed distribution and leeward side vortex around the HSRT caused by the wind speed fluctuation is found. The fluctuating amplitude of aerodynamic loads at the TBDC infrastructure is up to 97.9% larger than that at the TF infrastructure. Originality/value The natural wind characteristics at tunnel entrance sections on the high-speed railway are first measured and analyzed. A numerical reconstitution scheme considering the temporal and spatial variation of natural wind speed is proposed and verified based on field measurement results. The aerodynamic performance of an HSRT under reconstituted natural winds is first investigated.

show abstract

“…train nose shapes, shelters, windbreaks, air fences) on the distribution of velocity and the characteristics of the vortices are further investigated. [17][18][19][20] Maglev trains operate at high train speeds, with the track positioned relatively high above the ground and there isn't any bogies which is different from other trains. However, few investigation have been done to investigate the slipstream behaviour and vortices generated by maglev trains.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the slipstream characteristics of a maglev train in a tunnel

Liu

Zhou

Soper

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part F:

View full text Add to dashboard Cite

High-speed maglev trains operate at higher speeds than conventional high-speed trains. This has implications on intensified aerodynamic issues, such as the transition between open air running and entering into a tunnel. In this paper, numerical simulation of a maglev train entering a tunnel is carried out using IDDES methods (based on SST k-omega model) to analyze the changing slipstream. The peaks and fluctuations of the slipstream are analyzed, together with the transient wake characteristics and TKE (turbulent kinetic energy) distributions. The influence of train nose length on the slipstream and its associated characteristics inside tunnels is also investigated in this paper. It was found that as the maglev train enters the tunnel, the wake slipstream at measuring points close to tunnel entrance increases significantly then decreases slightly with the increase of distance to tunnel entrance. Overall, the fluctuation and magnitude of slipstream inside tunnel is larger than that on open line, more specifically, the maximum TKE generated inside tunnel is. 7.62% larger than that on the open line at contour X = 3 H behind the train tail. Besides it takes longer time for the slipstream inside tunnel to return to the initial condition. These phenomena could be explained by that the scale of vortex structure formed behind the train tail is larger, the developing distance of the wake vortices in the streamwise direction is longer and the TKE generated is more significant inside tunnel. It was also found that increasing the nose length could effectively decrease the spatial scale and TKE of the wake vortices, which resulted on reducing the peak and pulsation of wake slipstream. Comparing to that of 5.4 m, the peak of the wake slipstream of the maglev trains with the 7.4 m and 9.4 m nose lengths at Y = 0.235 m(0.385) is reduced by approximately 23.7%(58%) and 35.9%(82.2%) on open field, and by about 3.6%(4.7%) and 14%(18.5%) inside tunnel. Besides, the maximum TKE at contour X = 2H/3H/5H behind the train tail decreases about 14.4%/10.7%/11.3% and 51%/31.5%/18% as the nose length increase to 7.4 m and 9.4 m respectively.

show abstract

The optimum model determination of porous barriers in high-speed tracks

Cited by 22 publications

References 51 publications

Interaction Simulation of a Lateral Wall Distance on Aerodynamic Characteristics of a Simplified High-speed Train

Interaction Simulation of a Lateral Wall Distance on Aerodynamic Characteristics of a Simplified High-speed Train

Field test and numerical reconstitution of natural winds at the tunnel entrance section of high-speed railway

Numerical investigation of the slipstream characteristics of a maglev train in a tunnel

Contact Info

Product

Resources

About