Purpose

Sustainable urban rail transit requires noise barriers. However, these barriers’ durability varies due to the differing aerodynamic impacts they experience. The purpose of this paper is to investigate the aerodynamic discrepancies of trains when they meet within two types of rectangular noise barriers: fully enclosed (FERNB) and semi-enclosed with vertical plates (SERNBVB). The research also considers the sensitivity of the scale ratio in these scenarios.

Design/methodology/approach

A 1:16 scaled moving model test analyzed spatiotemporal patterns and discrepancies in aerodynamic pressures during train meetings. Three-dimensional computational fluid dynamics models, with scale ratios of 1:1, 1:8 and 1:16, used the improved delayed detached eddy simulation turbulence model and slip grid technique. Comparing scale ratios on aerodynamic pressure discrepancies between the two types of noise barriers and revealing the flow field mechanism were done. The goal is to establish the relationship between aerodynamic pressure at scale and in full scale.

Findings

The aerodynamic pressure on SERNBVB is influenced by the train’s head and tail waves, whereas for FERNB, it is affected by pressure wave and head-tail waves. Notably, SERNBVB's aerodynamic pressure is more sensitive to changes in scale ratio. As the scale ratio decreases, the aerodynamic pressure on the noise barrier gradually increases.

Originality/value

A train-meeting moving model test is conducted within the noise barrier. Comparison of aerodynamic discrepancies during train meets between two types of rectangular noise barriers and the relationship between the scale and the full scale are established considering the modeling scale ratio.

中文翻译：

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高速列车在两种类型隔音屏障内的气动差异：考虑建模比例

 目的

可持续的城市轨道交通需要隔音屏障。然而，这些屏障的耐用性因其所经历的不同的空气动力学影响而有所不同。本文的目的是研究列车在两种类型的矩形隔音屏障内相遇时的空气动力学差异：全封闭式 (FERNB) 和带有垂直板的半封闭式 (SERNBVB)。该研究还考虑了这些场景中比例比的敏感性。

设计/方法论/途径

1:16 比例的移动模型测试分析了列车会议期间的时空模式和空气动力压力差异。三维计算流体动力学模型，比例为1：1、1：8和1：16，采用改进的延迟分离涡模拟湍流模型和滑移网格技术。比较了两种类型隔音屏障之间气动压力差异的比例，并揭示了流场机制。目标是建立大尺度和全尺度的空气动力压力之间的关系。

 发现

SERNBVB 的气动压力受列车头尾波影响，而 FERNB 则受压力波和头尾波影响。值得注意的是，SERNBVB 的气动压力对比例的变化更加敏感。随着比例减小，声屏障上的空气动力压力逐渐增大。

 原创性/价值

在隔音屏障内进行列车会动模型试验。比较了两种矩形声屏障在列车相遇时的气动差异，并考虑建模比例，建立了比例尺与满比例的关系。