Wind tunnel tests on railway vehicles in the presence of windbreaks: Influence of flow and geometric parameters on aerodynamic coefficients

Crosswind stability is one of the most studied topics in the field of train aerodynamics. The interaction between a train and strong crosswinds can lead to the train overturning. One way to reduce the train overturning risk is to equip the railway line with windbreak barriers. In this work, the results obtained during wind tunnel tests on an ETR1000 high-speed train in the presence of different types of windbreaks are shown. The goal is to underline the effects of different flow parameters and geometric parameters of the infrastructure's models on the train's aerodynamic coefficients. Comparing the different test results made it possible to provide indications on which parameters are important to avoid experimental errors and reproduce as much as possible the real full-scale phenomena. Particular attention shall be paid to the dimensions of the splitter plate because a limited upwind width can lead to underestimation of aerodynamic coefficients by more than 30%. The length of the barriers in front of the train is fundamental and too short length can lead to coefficients overestimation of about 25%. Finally, coefficients measured with only the upwind windbreak row are lower (up to 50%) than those measured with a two rows configuration.