<p>In order to simplify the numerical calculation, previous studies assume that the train surface is smooth. In fact, the surface of the train is irregular, which affect the flow characteristics in the boundary layer near the wall, hence potentially influencing the aerodynamic performance of a train. In this work, roughness was applied to the roof of a 1:25 scaled train model in the form of longitudinal strips. Firstly, using improved delayed detached eddy simulation (IDDES) method to simulate the train model with a 90° yaw angle, with smooth or rough surface. Results show that the side force coefficient and the roll moment coefficient subjected to rough model decreased by 3.7% and 9.1% compared with smooth model. Based on this, selecting the length, width, and height of the strips as the variables to be investigated, taking the side force coefficient and the roll moment coefficient of the train model as the evaluation index, and 18 schemes are designed based on the orthogonal design method. Analysis of Variance and regression analysis are used to discuss the numerical calculation results. It can be found that the height of the strips has a greater impact on the side force coefficient and the roll moment coefficient, but the impact on the roll moment coefficient is more significant. In addition, the height of the strips is positively related to the side force coefficient and positively related to the roll moment coefficient. These conclusions can provide new ideas and reference basis for improving the aerodynamic performance of the high-speed train subjected to crosswind.</p>

Influence of Rectangular Strips’ Size on Aerodynamic Performance of a High-Speed Train Subjected to Crosswind

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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