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The turbulence intensity and yaw angle of crosswinds exert a substantial impact on the aerodynamic characteristics of trains traveling in windy regions. It is urgent to study how the yaw angle and turbulence intensity of incoming flow jointly affect the aerodynamic characteristics of the train and the corresponding flow field under turbulent crosswind. A high-speed train scaled at a ratio of 1/8 of its actual size at different yaw angles was investigated. Three inflow conditions were adopted, including uniform inflow, Iu = 0.05 inflow, and Iu = 0.2 inflow (Iu is turbulence intensity). The turbulent inflow was generated by the synthetic eddy method. The instantaneous and time averaged characteristics of aerodynamic loads and pressure loads of the train were analyzed. The vortex structures, vorticity, swirling strength, mean velocity, reverse flow, and Reynolds stresses are analyzed to explore the flow pattern and flow evolution. The results found that the fluctuation of the aerodynamic loads, the average side fore, and the average rolling moment of the train are remarkably enhanced under turbulent inflow. These results stem from the alterations in the flow field around the train induced by turbulent inflow, consequently leading to variations in surface pressure on the train. As the turbulence intensity of the inflow increases, the stability of the vortex structures decreases, and the position of the large-scale vortex structure has been changed. Moreover, the yaw angle (β) exerts a more significant influence on the vortex structure's flow pattern on the leeward side compared to the inflow turbulence intensity. [ABSTRACT FROM AUTHOR]

Turbulent incoming flow conditions are closely matched to the crosswinds experienced by trains in windy areas. Therefore, it is important to investigate how the turbulent inflow affects the flow dynamics around a train. The aerodynamic characteristics of a 1:8-scaled high-speed train at a 90° yaw angle were studied based on the improved delayed detached eddy simulation (IDDES) turbulence model. Four incoming flow conditions were set using a synthetic eddy method (SEM) turbulent generator, including uniform, Lu = 0.5H, Lu = 1H, and Lu = 2H inflow (Lu is turbulence integral length scale and H is reference height). The aerodynamic loads, surface pressure, mean vorticity, vortex structure, velocity deficit, turbulence characteristics, Reynold stresses, turbulence production term, and anisotropy of turbulence were thoroughly analyzed. Turbulent inflow and increasing inflow Lu increased the standard deviation of the aerodynamic loads on the train. A crisis of inflow Lu appeared around 0.5H, meaning the rolling moment and overturning moment were largest under this crisis condition. Turbulent inflow caused vortices on the train's leeward side to come closer to the train, increasing the vorticity thickness and shortening the back flow region. The Reynolds stresses on the train's leeward side under turbulent inflow conditions were strengthened. The spectrum-proper orthogonal decomposition method was used to analyze the dominant mode within the train's leeward region and the corresponding energy distribution in the frequency domain. The aerodynamic admittance function was used to investigate the frequency characteristics of the aerodynamic loads on the train. [ABSTRACT FROM AUTHOR]

Transient aerodynamic pressures induced by the passage of high-speed trains past noise barriers can result in noise barrier damage. This issue is investigated experimentally in the present study by applying pressure sensors to measure the transient aerodynamic pressures acting on the inner surface (close to the railway track) of a 2.15-m high straight-type noise barrier arising from the passage of two different full-scale high-speed trains with different streamlined head cars operating at a speed of 380–420 ​km/h. The results demonstrate that the amplitudes of transient aerodynamic pressures acting on the inner surface of the noise barrier are greatest at the bottom of the noise barrier, and the pressure decreases with increasing height along the barrier. In addition, the dynamic characteristics of the aerodynamic loads are investigated using the fast Fourier transform algorithm. The main frequencies of the transient aerodynamic pressures observed over the train speed range considered are found to be proportional to the train speed and inversely proportional to the single-car length. Moreover, the results of analysis indicate that noise barrier damage can be minimized over the train speed range considered by building noise barriers with natural frequencies residing outside of the 4.21–4.74 ​Hz range. • Full-scale experiment about transient pressure on noise barrier induced by high-speed trains running at 380–420 km/h. • The amplitudes characteristics of transient aerodynamic pressures acting on the surface of the noise barrier. • The main frequencies of the transient aerodynamic pressures at different train speed. [ABSTRACT FROM AUTHOR]