A novel diffusive wind barrier protecting trains from crosswinds on bridges, and its performance evaluated under various skew and attack angles

Journal article, 2025

This study introduces the diffusible diversion case (DDC), a novel wind barrier designed based on the original porous case (OPC), and compares their performance in protecting trains from crosswinds. The study begins with 0° crosswinds and progresses to those with skew angles (15°-75°) and angles of attack (±10°). A Reynolds-averaged Navier-Stokes model with a standard k-ϵ turbulence model is used for the turbulent flow analysis and validated against wind tunnel experimental data. Results show that the DDC significantly outperforms the OPC under 0° crosswinds. The airflow that initially impacts the windward side of the train is deflected upward and downward by the DDC, creating a low-speed zone along with a large vortex between the DDC and the train. This reduces the lateral force on the train by 88.24% and the overturning moment by 47.52%. Meanwhile, DDC offers superior protection against crosswinds with varying angles. When facing various skew winds, the DDC continues to mitigate airflow impacts on the windward side and generate positive pressure zones. Compared to the OPC, the DDC provides a broader outstanding protection range, thereby enhancing train operability, achieving a 46.64% reduction in lateral forces. Additionally, the DDC shows little sensitivity to attack angle variations in crosswinds, exhibiting a 54.94% reduction with a positive change in angle and a 66.56% increase with a negative change compared to the OPC. With positive attack angles, DDC decreases the overturning moment by 64.33% and by 20.26% in negative angles. This study provides insight into designing wind barriers for train protection on railway bridges, enhancing safety and efficiency in windy areas.