Experimental study on the spanwise correlation of buffeting forces of the train under the stationary thunderstorm downburst wind

Abstract

To study the spanwise correlation characteristics of buffeting forces of the train under the stationary thunderstorm downburst wind, a thunderstorm downburst wind test device was used to simulate the thunderstorm downburst wind fields over two types of surface roughness. Based on rigid model pressure measurement test, the radial wind profiles of the stationary thunderstorm downburst wind and the surface pressures of the train at different radial distances were obtained. The study investigated the effects of radial distance on the train’s aerodynamic force coefficient and surface pressure coefficient. Based on this, it analyzed the influence of radial distance and spanwise spacing on the spanwise correlation of buffeting forces in the time domain. Additionally, a comparative analysis was conducted between the spanwise correlation of buffeting forces and the spanwise correlation of fluctuating wind. The research results show that compared to atmospheric boundary layer wind fields, the distribution of the thunderstorm downburst wind fields exhibits significant non-uniformity in their spanwise distribution. Under the thunderstorm downburst wind, the total aerodynamic coefficient and radial wind speed of the train vary with radial distance. When the radial distance r/D_j = 1, the radial wind speed reaches its maximum value. As surface roughness increases, the lift coefficient and the RMS value of fluctuating wind pressure coefficient at the junction between the top and the windward side increase, while the lateral force coefficient and radial wind speed decrease overall. Simultaneously, radial wind speed decays more significantly in the outer region (r/D_j > 1), radial distance significantly influences the correlation coefficient of buffeting forces. Additionally, the correlation coefficient of buffeting forces gradually decreases with increasing spanwise spacing, indicating a weakening spatial correlation. The correlation for lateral forces is superior to that for longitudinal and vertical fluctuating wind, while the correlation of moment is relatively weaker.

Keywords

thunderstorm downburst wind / spanwise correlation / buffeting forces / high-speed train / experimental study

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Central South University