旋转列车气流的大涡模拟

利用大涡模拟(LES)方法研究高速列车的气流问题,采用标准的Smagorinsky模型模拟亚格子应力。列车模型是由4辆车组成的1/25比例的ICE 2型列车。该模型被放置于直径为3.61m的旋转试验台上。基于列车的高度和速度,分别对雷诺数77 000和94 000的大涡进行了模拟。模拟中运用了粗糙的、中等的和加密的3种计算网格。加密网格的计算结果与试验数据吻合较好。运用大涡模拟获得了不同的流动区域。研究表明,以柱面形式支撑的风挡和车下复杂结构对气流的速度有很大的影响。在合适的雷诺数范围内,气流流速与列车速度近似地呈线性关系。

The Large-Eddy Simulation of the Slipstream of a Rotating Train

The slipstream of a high speed train was investigated using large-eddy simulation （LES） . The sub-grid stresses were modeled using the standard Smagorinsky model. The train model consisted of a fourcoach of a 1/25 scale of the ICE 2 train. The model was attached to a 3.61 m diameter rotating rig. The LES was made at two Reynolds numbers of 77 000 and 94 000 based on the height of the train and its speed. Three different computational meshes were used in the simulations： coarse, medium and fine. The results of the fine mesh are in fairly agreement with the experimental data. Different flow regions were obtained using the LES. The intercarriage gaps and the underbody complexities, in the form of supporting cylinders, were shown to have large influences on the slipstream velocity. The results showed that the slipstream velocity is linearly proportional to the speed of the train in the range of our moderate Reynolds numbers.