中文摘要：

高速列车通过跨线天桥结构时在天桥与高速列车之间的狭小空间内产生较大的局部风压,跨线天桥结构对局部风压的高频脉动成分极为敏感。为了探究脉动成分的大小,采用CFD数值模拟,运用滑移网格技术,大涡模拟湍流模型（LES）对高速列车经过跨线天桥结构周围的三维、非定常、可压缩流场进行模拟,并与跨线天桥实测结果吻合。对保留脉动成分的LES模拟结果在时域上进行分析,探究脉动成分分布的位置,脉动极值空间分布,以及脉动风能量在列车风压中所占比例,同时在频域上采用小波包分析的方法对LES结果进行分解,分析各频段风压能量分布规律。研究结果表明：跨线天桥表面风压脉动成分极小。

英文摘要：

High-speed train passing through the bridge structure causes a great local pressure in the small space between the bridge and the high-speed train, while the bridge structure across the line is extremely sensitive to the fluctuating wind pressure . In order to study the size of the fluctuating wind pressure, we simulate the three-dimensional, unsteady, compressible flow field while high-speed train passing through the bridge across the line using numerical simulation CFD, sliding mesh technique, large eddy simulation turbulence model （LES） and the results squares with the measured data. Via analyzing the LES simulation results in the time domain, we explore the position of the fluctuating part, pulsating extreme spatial distribution, as well as the proportion of fluctuating wind energy in total pressure energy.While in the frequency domain we decompose LES results using wavelet packet analysis, analyzing the energy distribution of the band pressure. The results showed that： the fluctuating wind pressure across the bridge is very small.