高速列车相对于其它运输方式，在节省能源消耗和降低碳排量方面具有较大优势，然而随着列车运行速度的增加，气动阻力在总阻力中的占比也在不断增大，不仅制约了高速列车节能环保的能力，而且限制了高速列车的进一步提速。传统的减阻方法在降低列车阻力方面所发挥的作用有限，因此寻求新型的减阻方法是迫切需要解决的问题。本文以CRH380A型号列车为研究对象，基于流动控制理论，提出一种侧向导流装置，并研究了导流装置的形状、拉伸高度以及安装方式对列车气动阻力的影响。

首先，根据风洞试验的设置条件，构建了相应的计算模型，在特定的网格拓扑和计算方法的条件下，对比了数值计算和风洞试验的结果，发现整车阻力系数的误差小于4%，满足工程计算的精度要求，验证了网格拓扑和数值计算方法的有效性。

其次，本文构建了含参数的函数，以控制导流装置的形状。将拉伸高度为15cm的导流装置安装在头车排障器底面，研究导流装置形状对列车气动阻力的影响，结果表明形状参数0.9对应的导流装置具有最大的整车减阻率。在相同条件下，进一步研究了形状参数0.9和5.5对应的导流装置的拉伸高度对列车气动阻力的影响，发现整车气动阻力均随着拉伸高度的增加而降低。将形状参数0.9对应的拉伸高度为15cm的导流装置安装在列车底面的不同位置，研究了导流装置的安装方式对列车气动阻力的影响，结果表明仅在头车排障器底部安装导流装置可以取得最好的减阻率。

最后，以在头尾车排障器底部对称安装导流装置的情况为例，分析了底部导流装置的减阻机理，发现在头车排障器底部安装的导流装置将前方的部分气流导向了两侧并在其后形成了一系列尾涡，避免了高速气流对转向架区域的冲击，加速了气流能量的耗散，从而有效降低了转向架区域的压差阻力。

Compared with other transport, high-speed trains have great advantages in saving energy and reducing carbon emissions. However, with the increase of train speed, the aerodynamic drag accounts for an increasing proportion of the total drag, which not only restricts the energy-saving and environmental protection capabilities of high-speed trains, but also limits the further speed increase of high-speed trains. Traditional drag reduction methods play a limited role in reducing the drag of trains. Therefore, seeking a new type of drag reduction method is an urgent problem to be solved. The CRH380A train is selected as the research object in the paper. Based on the flow control theory, side diversion structures are proposed, and the influence of the shape, height and installation configurations of diversion structures on the aerodynamic drag of high-speed trains is investigated.

First, the corresponding computational model is constructed, which conforms to the experiment conditions of wind tunnel. The error between experimental results and numerical simulation results that is based on the specified mesh topology and computational method is less than 4%, which meets the accuracy requirement of engineering calculation and verifies the effectiveness of mesh topology and numerical computation method.

Secondly, a function with parameters is proposed in the paper to control the shape of diversion structure. The diversion structures with same height of 15cm are installed on the bottom surface of head train pilot and the influence of shape of diversion structure on the aerodynamic drag of high-speed trains is investigated. The results show that the diversion structure corresponding to shape parameter 0.9 has the best drag reduction rate of the whole train. Under the same conditions, the influence of heights of the diversion structure corresponding to the shape parameters 0.9 and 5.5 on the aerodynamic drag of the train is further studied, and it is found that the aerodynamic drag of the whole train decreases with the increase of structure heights. The diversion structures with the height of 15cm corresponding to the shape parameter 0.9 are installed at different positions on the bottom surface of high-speed trains, and the influence of configuration of diversion structures on the aerodynamic drag of high-speed trains is further investigated. The results show that the best drag reduction rate can be achieved by installing the diversion structure only on the bottom surface of head train pilot.

Finally, taking the case that two diversion structures are installed at the bottom surface of pilots of head train and tail train as an example, the drag reduction mechanism of the diversion structure installed at the bottom of high-speed trains is analyzed, and it is found that the diversion structure directs part of the its front air to both sides, and a series of wake vortexes are appeared behind it. As a result, the impact of high-speed air on the bogie area is avoided, and the dissipation of air energy is accelerated, thereby effectively reducing the pressure drag of bogie zones.