The effect of moving train on the aerodynamic performances of train-bridge system with a crosswind

Abstract

Some aerodynamic results about the effect of moving train on the aerodynamics of train-bridge system in crosswinds are introduced using a computational fluid dynamics (CFD) method. In the simulation, a new overset mesh approach is applied to present the motion of trains, and the results are compared with that of the scaled wind tunnel experiment to validate the accuracy of the mesh and algorithm. Besides, the aerodynamic characteristics associated with the train and bridge are discussed for a range of resultant yaw angles. It is found that the resultant yaw angle is significantly important for the aerodynamic performances of trains, and the aerodynamic interaction on the nose of head-car can affect the flow features around train-bridge system to produce larger aerodynamic loads on the head-car. Furthermore, a new fitting formula for some resultant yaw angles is proposed to predict the aerodynamic forces on trains. Finally, the time-varying forces on the bridge are presented and a sudden change of aerodynamic loads is also observed due to the effect of moving train. The variation magnitude of forces depends on the train speed, and the mean value of forces is only determined by the natural wind velocity.

Numerical Study of the Unsteady Aerodynamic Performance of Two Maglev Trains Passing Each Other in Open Air Using Different Turbulence Models

“…In the numerical simulation, two trains passing each other and the relative motion between the train and other railway infrastructures (e.g., tunnels, wind barriers, and bridges) can be analysed using the dynamic mesh method [33,34], sliding mesh method [1,[35][36][37], and overset mesh method [12,21,38,39]. Nevertheless, the dynamic mesh method needs to regenerate the mesh at each time step, which may increase the calculation time.…”

“…However, the number of grids required for the sliding mesh method is greater than that required for the overset mesh method with the same grid refinement method. Furthermore, the overset mesh method is suitable for complex and irregular moving models owing to its decomposition and overlapping techniques [39]. Consequently, the overset mesh method was applied in this study.…”

Numerical investigation on the crosswind effects on a train running on a bridge

“…Unsteady incompressible N-S equations are used to solve the flow field for the cases with a train running on the bridge and pass by the wind barrier. A Shear Stress Transport (SST) turbulence model is widely used in numerical simulation of the flow around the train (Liang et al, 2020;Yao et al, 2020), which is designed to deal with adverse pressure gradients and separated flows (Menter et al, 2003). The SST k-ω turbulence model is used as the turbulence closure for the RANS equations listed below:…”

“…wind/sound barriers. Recently, some moving model tests have been carried out to highlight the unsteady characteristics of the aerodynamic forces caused by a running train under crosswind (Wang et al, 2018;Yao et al, 2020).…”

Influence of height of earth embankment type windbreak wall on flow field characteristics and catenary wind-induced displacement

“…Many scholars have suggested that to cope with severe weather, which includes wind and sandstorm, to ensure the safe operation of trains in strong winds, and to improve the aerodynamic performances of trains, windbreaks should be built along the railways (Baker, 1986;Barcala & Meseguer, 2007;Bocciolone et al, 2008;Chu et al, 2013;He et al, 2014;T. Liu et al, 2018;Niu et al, 2018;Yao et al, 2020). Xinjiang has a special geographical location and a complex CONTACT Tanghong Liu lth@csu.edu.cn; Yutao Xia xytcsu@csu.edu.cn climatic environment.…”