基于CFD的洪涝水流中车辆失稳阈值研究

高丽军; 陈韬; 李俊奇; 李小静; 王晓哲

doi:10.13928/j.cnki.wrahe.2025.01.002

水利水电技术（中英文） ›› 2025, Vol. 56 ›› Issue (1) : 15 -25. DOI: 10.13928/j.cnki.wrahe.2025.01.002

复合极端天气气候事件与洪涝灾害机理专栏

基于CFD的洪涝水流中车辆失稳阈值研究

高丽军 ¹^,² ,
陈韬 ¹^,² ,
李俊奇 ¹^,² ,
李小静 ¹^,² ,
王晓哲 ¹^,²

作者信息 +

Instability threshold of vehicles in floodwaters based on CFD

Lijun GAO ¹^,² ,
Tao CHEN ¹^,² ,
Junqi LI ¹^,² ,
Xiaojing LI ¹^,² ,
Xiaozhe WANG ¹^,²

Author information +

文章历史 +

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摘要

【目的】道路行泄通道是大排水系统的核心组成部分，为保障道路在发挥行泄通道作用时车辆的安全与稳定性，【方法】以典型轿车奥迪A4L作为研究对象，利用最优拉丁超立方抽样选取洪涝水流的流速与水深，采用VOF方法，通过CFD数值模拟计算车辆受到的水流作用力并分析车身附近的水流自由液面高度变化，揭示车辆在不同水流条件下的失稳机理。【结果】结果显示：车辆受到的水流阻力与浮力同时受到水深与流速的影响，阻力系数的值稳定在一定范围内，水流自由液面高度的剧烈变化显著影响车辆受到浮力的大小。【结论】结果表明：当流速小于1 m/s时，失稳水深阈值为0.4 m;当流速介于1 m/s和4.5 m/s之间，摩擦系数为0.25或0.35时对应的失稳水深阈值可分别用关于流速的三次函数来表达；当流速为4.5 m/s时，失稳水深阈值分别为0.24 m(μ=0.25)和0.27 m(μ=0.35);最不利失稳阈值曲线下方区域为安全区，2条曲线之间的区域定义为失稳风险区。研究成果可为道路行泄通道车辆失稳风险评估提供参考。

Abstract

[Objective] The surface flood pathway is a critical component of major drainage system. To ensure the safety and stability of vehicles when the road plays the role of drainage path, [Methods] Audi A4L was selected as the research object. The optimal Latin hypercube design was used to select the flow velocity and water depth of the flood. The VOF method and CFD numerical simulation are used to calculate the flow force on the vehicle and analyze the change of the free water level near the vehicle body, so as to reveal the instability mechanism of the vehicle under different flow conditions.[Results] The result show that the drag force and buoyancy of the vehicle are affected by the water depth and velocity at the same time. The value of the drag coefficient is stable within a certain range, and the buoyancy of the vehicle is significantly affected by the drastic change of the free surface height of the water flow.[Conclusion] When the flow velocity is less than 1 m/s, the threshold of instability water depth is 0.4 m; When the flow velocity is between 1 m/s and 4.5 m/s, and the friction coefficient is 0.25 or 0.35, the threshold of instability water depth can be expressed as a cubic function of the flow velocity; When the flow velocity is 4.5 m/s, the threshold of instability depth is 0.24 m(μ=0.25) and 0.27 m(μ=0.35). The area below the curve of the most unfavorable instability threshold is the safe zone, and the area between the two curves is defined as the instability risk area. Research result can provide reference for the risk assessment of vehicle instability in the roadway drainage path.