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The development of high-speed railway networks and the increased running speeds of high-speed trains (HSTs) have made the aerodynamic interference between HSTs and their surrounding environments increasingly important. Compared with a traditional wind tunnel test, systematically understanding the aerodynamic characteristics of HSTs involves relatively more stringent requirements, highlighting the need to develop experimental methods and technologies with enhanced dynamic performance. Central South University (CSU) developed a wireless data acquisition system, named as the in-model sensory and wireless data acquisition — remote control and processing system (ISWDA-RCPS), which can operate onboard a novel moving train and infrastructure rig. The system was developed to meet current wind tunnel data collection needs, and it avoids the physical cables used in conventional devices, which are extremely susceptible to induced noise. The system accepts inputs from various sensors and transfers the data wirelessly to an access point outside a wind tunnel’s test section. To analyze the feasibility of the ISWDA-RCPS concerning its sensing capabilities and wireless communications, we conduct experiments in multiple operating conditions. Finally, pressure measurements are acquired from a moving Fuxing HST model at different points and used to analyze the aerodynamic behavior of the model. [ABSTRACT FROM AUTHOR]

To better understand the aerodynamic characteristics of a train-bridge system under crosswind, an in-house experimental apparatus was developed in a wind tunnel at Central South University (CSU). The new facility consists of trains, a bridge, U-shaped slide rails, and positioning systems with winches. A wireless data acquisition system for pressure measurements was mounted within the train carriage to avoid any potential aerodynamic interference. A 1:25 scaled model of CRH2 running over a simply supported girder bridge was tested in a wind tunnel. The aerodynamic characteristics of the train-bridge system under various combinations of crosswind speed, train speed, and vehicle location on the bridge were identified. The experimental results reveal that the cosine law for surface wind pressure on a train under crosswind is no longer valid when the train runs on the bridge. The moving model method can better capture the more practical aerodynamic characteristics and the impact of train movement on the bridge. The present study indicates that the wind tunnel experiments using the stationary model cannot fully reveal the aerodynamic characteristics of both the train and bridge during crossing. The results captured using this unique approach provide insight into the aerodynamic characteristics of trains and bridges. [ABSTRACT FROM AUTHOR]

• Aerodynamic characteristics of a typical high-speed railway viaduct under tornado near-ground winds were studied. • Surface pressure coefficients of the bridge deck vary from place to place within the tornado. • Largest side and lift forces occur at the tornado core, but the change patterns of forces in different types with the variation distance. • Research findings are helpful for the design, operation & maintenance of high-speed railway bridges. The tornado is in direct contact with the underlying surface, which causes damage and indicates the vortex structure close to the ground. Accordingly, the maximum wind velocity generally could occur near the ground, potentially exposing the infrastructure to higher wind loads. However, one of the biggest challenges facing tornado research is characterizing the wind structure very near the surface due to the limitation of the data by using Doppler weather Radar. Considering the advantage of the high-fidelity computational fluid dynamics (CFD) models, this study aims to investigate the aerodynamic characteristics of a high-speed railway viaduct under tornado near-surface winds. More specifically, in light of limited full-scale data to arrive at a consensus on quantifying key parameters characterizing the tornado flow and near-surface winds, firstly. Secondly, tornado radar-measured data and a theoretical analysis model were utilized to validate the accuracy of the numerical method adopted in this study. Thirdly, the wind pressure distribution on the bridge is validated using the wind tunnel experimental data in Central South University(CSU), and the comparison between the simulational bridge and the measured data under crosswind was satisfactory. Finally, a comprehensive modeling strategy comprehensively investigates the aerodynamic characteristics of a high-speed railway viaduct under a tornado near-surface wind. [ABSTRACT FROM AUTHOR]