障碍板尾涡与运动物体壁湍流涡干涉机理大涡模拟研究

高速列车侧风稳定性问题是列车空气动力学的重要研究课题之一，挡风墙、防风栅等结构常用于大风区高速列车防风工程。本项目以我国兰新第二双线这一典型的大风区高速铁路为背景，在归纳梳理防风工程实际情况和前期研究成果的基础上，按照去繁就简、去伪存真原则，从大风绕流挡风墙尾涡与高速列车壁湍流涡旋结构的相互作用出发，针对实际工程应用中发现的列车横向低频晃动问题，建立障碍板尾涡与运动物体壁湍流涡干涉机理研究的三维非定常湍流流动数学物理模型。采用湍流流动的大涡模拟方法研究障碍板尾涡区的横向涡旋与运动物体壁湍流纵向涡的相互干涉机理，归纳障碍板高度、距运动物体的距离、不连续结构的形状参数等几何要素对涡干涉机理的影响规律，探讨空气流速和风向角、运动物体速度等对运动物体空气动力和力矩非定常特性的影响，深化和拓展挡风墙后高速列车非定常空气动力本质特性的认识，可望为大风区新建线路的防风工程设计提供一定的理论支撑。

The rolling stability of high-speed trains under crosswind is one of the most important issues in the aerodynamics of the high-speed railway trains. Wind-defense walls, windbreaks, and other structures are usually built along high-speed railway as wind-proof engineering in strong cross-wind areas. Based on careful review of actual situations of wind-proof engineering and various research results on high-speed railway from Lanzhou to Urumchi, which is a typical railway line affected by strong wind in China, the present work is to extract a conceptual numerical physical analysis model of vortices interference between the turbulent air flow after a ground obstacle and that around a moving object running behind, from vortices interference between turbulent flow after wind-break and that around a high-speed train running behind. The extraction follows the principle of ‘To simplify by deleting the complexity, to eliminate the falsehood and retain the truth’. The various factors affecting the lateral swaying of the train at low frequency will be examined and selected. Large eddy simulation of turbulent air flow will be performed to study the mechanism of the vortices interference between the large-scale lateral eddies behind the ground obstacle and the small-scale longitudinal vortices around the moving object running behind it at high speed. The influence of the obstacle height, the distance from the moving object, the discontinuous structures and other geometric factors on the vortices interference mechanism will be thoroughly summarized. The unsteady performance and frequency characteristics of the aerodynamic forces and moments of the moving object at different speeds will be discussed, which will be helpful to deepen and extend the knowledge of the usage of windbreak. Effect of wind velocity and the angle between air flow direction and moving object will be also considered. The understanding of or insight into the unsteady nature of the aerodynamic performance of high-speed trains behind a windbreak is expected to provide certain theoretical support for wind-proof engineering design of new railways in strong cross-wind areas in future.