通过采用三维瞬态DDES数值方法模拟强横风下,在路堤上运行的高速列车周围流场,对比3,6,9和12 m 4种路堤高度对高速列车瞬态气动性能的影响。研究结果表明:强横风下,随着路堤高度的增加,列车两侧压力差增大,并影响列车周围流速分布,使得...通过采用三维瞬态DDES数值方法模拟强横风下,在路堤上运行的高速列车周围流场,对比3,6,9和12 m 4种路堤高度对高速列车瞬态气动性能的影响。研究结果表明:强横风下,随着路堤高度的增加,列车两侧压力差增大,并影响列车周围流速分布,使得流场情况更为复杂。瞬态流场结构显示,在路堤高度增加之后,车体背风侧的涡结构逐渐由体积较小、脉动频率较高、能量较小的分离状逐渐转变为融合度更高、体积更大、脉动频率较低、能量较大的涡结构,将会使得车体运动的稳定性受到更大影响,更容易发生倾覆危险。从气动力来看,随着路堤高度的增加,头车受到的气动载荷增加较大。展开更多
Using structured mesh to discretize the calculation region, the wind velocity and pressure distribution in front of the wind barrier under different embankment heights are investigated based on the Detached Eddy Simul...Using structured mesh to discretize the calculation region, the wind velocity and pressure distribution in front of the wind barrier under different embankment heights are investigated based on the Detached Eddy Simulation(DES) with standard SpalartAllmaras(SA) model. The Reynolds number is 4.0×105 in this calculation. The region is three-dimensional. Since the wind barrier and trains are almost invariable cross-sections, only 25 m along the track is modeled. The height of embankment ranges from 1 m to 5 m and the wind barrier is 3 m high. The results show that the wind speed changes obviously before the wind barrier on the horizontal plane, which is 4.5 m high above the track. The speed of wind reduces gradually while approaching the wind barrier. It reaches the minimum value at a distance about 5 m before the wind barrier, and increases dramatically afterwards. The speed of wind at this location is linear with the speed of far field. The train aerodynamic coefficients decrease sharply with the increment of the embankment height. And they take up the monotonicity. Meanwhile, when the height increases from 3 m to 5 m, they just change slightly. It is concluded that the optimum anemometer location is nearly 5 m in front of the wind barrier.展开更多
文摘通过采用三维瞬态DDES数值方法模拟强横风下,在路堤上运行的高速列车周围流场,对比3,6,9和12 m 4种路堤高度对高速列车瞬态气动性能的影响。研究结果表明:强横风下,随着路堤高度的增加,列车两侧压力差增大,并影响列车周围流速分布,使得流场情况更为复杂。瞬态流场结构显示,在路堤高度增加之后,车体背风侧的涡结构逐渐由体积较小、脉动频率较高、能量较小的分离状逐渐转变为融合度更高、体积更大、脉动频率较低、能量较大的涡结构,将会使得车体运动的稳定性受到更大影响,更容易发生倾覆危险。从气动力来看,随着路堤高度的增加,头车受到的气动载荷增加较大。
基金Projects(51075401,U1334205)supported by the National Natural Science Foundation of ChinaProject(NCET-10-0833)supported by the New Century Excellent Talents in University,China+2 种基金Project supported by the Scholarship Award for Excellent Innovative Doctoral Student granted by Central South University,ChinaProject(2012T002-E)supported by the Science and Technology Research and Development Program of Ministry of Railway,ChinaProject(14JJ1003)supported by the Natural Science Foundation of Hunan Province,China
文摘Using structured mesh to discretize the calculation region, the wind velocity and pressure distribution in front of the wind barrier under different embankment heights are investigated based on the Detached Eddy Simulation(DES) with standard SpalartAllmaras(SA) model. The Reynolds number is 4.0×105 in this calculation. The region is three-dimensional. Since the wind barrier and trains are almost invariable cross-sections, only 25 m along the track is modeled. The height of embankment ranges from 1 m to 5 m and the wind barrier is 3 m high. The results show that the wind speed changes obviously before the wind barrier on the horizontal plane, which is 4.5 m high above the track. The speed of wind reduces gradually while approaching the wind barrier. It reaches the minimum value at a distance about 5 m before the wind barrier, and increases dramatically afterwards. The speed of wind at this location is linear with the speed of far field. The train aerodynamic coefficients decrease sharply with the increment of the embankment height. And they take up the monotonicity. Meanwhile, when the height increases from 3 m to 5 m, they just change slightly. It is concluded that the optimum anemometer location is nearly 5 m in front of the wind barrier.
