Influence of wind barriers on the aerodynamic forces of trains on a bridge deck at different attack angles

This study investigates the effects of wind barriers on the aerodynamic forces of trains on a wide bridge girder at varying angles of attack (AOA). Through force measurement wind tunnel tests, the aerodynamic forces of trains were analyzed for single-train and train-intersection scenarios. Computational fluid dynamics simulations were employed to investigate the time-averaged wind speed field above the bridge girder and pressure distributions around the train section. A comparative analysis of aerodynamic forces was conducted between trains on the deck with parapets and the deck with wind barriers across varying AOA. Results demonstrated that the aerodynamic forces on a train were highly sensitive to AOA, with maximum values observed at non-zero AOA. The immersion of trains in the shear layer, reduced train side force while amplifying rolling moments compared to the case of trains on flat ground. The increase in AOA and installation of wind barriers increases the resulting shear layer thickness, thereby effectively reducing aerodynamic side forces and rolling moments. On the deck with parapets, the middle car experiences higher aerodynamic side force and lower lift force than the head car due to the pronounced end effects experienced by the head car. The installation of wind barriers diminishes aerodynamic forces disparities between head and middle cars, leading to comparable side forces at all tested AOA and lift forces at large AOA. Furthermore, it effectively suppresses negative pressure amplification on leeward surfaces of windward rail trains during train intersections, with this mitigation effect being particularly pronounced at non-negative AOA.