中文摘要：

主要针对缩尺比例1：30的高速动车组空气动力学模型的近尾流区域流场进行数值模拟,分析讨论了湍动能和湍流能量的产生,得到以下结论：对应于各展向位置的湍动能沿流向的变化规律与近尾流区涡旋结构携带能量的展向外移现象有关;在尾车鼻端附近,湍流涡旋具有显著的湍动能,并且各方向上的能量分量具有相同的量级,反映出湍流涡旋是高度三维的流动结构;靠近尾车鼻端的近尾流区湍流涡旋具有较强的从平均流动中提取能量的能力,并且结果表明,来自于车体底面和侧面的剪切流动沿垂向分别在一定空间范围内发挥重要的影响作用;大涡特征尺度沿流向增大,其中较小的涡旋对湍流能量的产生有主要贡献,同时,由于受到列车侧面较厚剪切层的影响,对湍流能量有贡献的涡旋所对应的积分尺度范围增大,从而使位于尾车鼻端附近的涡流能够在更大的流向范围内获取用于维持湍流尾流的能量.

英文摘要：

Flow field in the near wake of an aerodynamic train model （ATM） at 1：30 scale was numerically simulated in the present work, turbulence kinetic energy （TKE） and production of turbulent energy were analyzed and discussed. Several conclusions were drawn. Variation of TKE as a function of streamwise distance was observed for each coordinate in the spanwise direction, which could be attributed to spanwise movement of the near wake vortex structures with turbulent energy. Remarkable TKE was exhibited by the turbulent vortices in the near wake, close to the nose of the trailing car. Each component of the TKE in the streamwise, spanwise and normal directions gave the same order of magnitude, accordingly indicating the fact that the turbulent vortices must be highly three-dimensional flow structures. Furthermore, in the near wake around the nose of the trailing car, theturbulent eddies had a powerful ability to extract energy from the mean flow, and the numerical results suggested that, within the varied spans along the normal direction, the relatively major influences had to be exerted separately by the shear flows from the bottom and sides of the ATM body. Characteristic lengths of large eddies increased downstream along the streamwise direction, and significant contributions to production of turbulent energy were made by the smaller eddies. Meanwhile, due to the notably thick shear layers separated from the sides of the ATM body, the range of the integral length scale was increased for the larger eddies to generate more turbulent energy, and therefore the eddies near the nose of the trailing car did not lose the ability to obtain energy from the extended streamwise range to maintain the turbulent wake.