Numerical simulation of bus aerodynamics on several classes of bridge decks

Abstract

This paper is focused on improving traffic safety on bridges under crosswind conditions, as adverse wind conditions can increase the risk of traffic accidents. Two ways to improve traffic safety are investigated: improving vehicle stability by means of wind fences installed on the bridge deck and by modifying the design parameters of the infrastructure. Specifically, this study examines the influence of different parameters related to the bridge deck configuration on the aerodynamic coefficients acting on a bus model under crosswind conditions. The aerodynamic coefficients related to side force, lift force and rollover moment are obtained for three classes of bridge deck (box, girder and board) by numerical simulation. FLUENT was used to solve the Reynolds-averaged Navier-Stokes (RANS) equations along with the shear stress transport (SST) k-ω turbulence model. Two crash barriers located on the box bridge deck were replaced with an articulating wind fence model and the effect of the angle between the wind fence and the horizontal plane on the bus aerodynamic was investigated. The risk of rollover accidents was found to be slightly influenced by the bridge deck type for a yaw angle range between 75°and 120°. In order to study the effect of the yaw angle on the aerodynamic coefficients acting on bus, both the bus model and the bridge model were simultaneously rotated. The minimum value of the rollover coefficient was obtained for an angle of 60°between the wind fence slope and the horizontal plane. The only geometry parameter of the box bridge deck which significantly affects bus aerodynamics is the box height. The present research highlights the usefulness of computational fluid dynamics (CFD) for improving traffic safety, studying the performance of the articulating wind fence, and determining which geometry parameters of the box deck have a significant influence on the bus stability.

Capability analysis of computational fluid dynamics models in wind shield study on Queensferry Crossing, Scotland

“…The results also showed that the sudden changing of the aerodynamic forces caused by the tower may be shorter than the average driver reaction time and thus the influence of crosswinds on lightweight vehicles such as buses and trucks can induce traffic accidents, even when exposed to relatively low wind velocities. Alonso-Estébanez et al (2017) studied the performance of an articulating wind shield by investigating the effect of the angle between the wind shield and the horizontal plane on vehicle aerodynamics. Results indicated that the articulating wind shield was better at protecting vehicles from crosswinds than crash barriers alone.…”

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

“…There have been many pieces of research to estimate the aerodynamic behaviors of the train under a crosswind environment using the full-scale experiments, scaled wind tunnel tests and CFD simulations CONTACT Nan Zhang nzhang@bjtu.edu.cn (Alonso-Estébanez, Del Coz Díaz, Álvarez Rabanal, & Pascual-Muñoz, 2017;Baker, Jones, Lopez-Calleja, & Munday, 2004;Gallagher et al, 2018;Niu, Zhou, & Liang, 2018;Suzuki, Tanemoto, & Maeda, 2003). In these investigations, usually the train runs on the flat ground or embankment, and the movement of the train is created by means of the resultant velocity V r imposed on a static vehicle, as seen in Figure 1, depending on the train speed V t and incoming wind speed V w with a wind angle of α.…”

“…Besides, for the train-bridge system with a moving vehicle, it is not easy to measure the aerodynamic forces on the bridge. At the same time, with the rapid development of computer technology, the CFD approach is also widely approved and adopted in the studies (Alonso-Estébanez et al, 2017;Mosavi, Shamshirband, Salwana, Chau, & Tah, 2019;Niu et al, 2018;Sun, Song, & An, 2012;Yao, Guo, Sun, & Yang, 2015;Zhang, Yu, Zhang, Wu, & Li, 2019), which can better capture the flow characteristics around train-bridge system and easily obtain the aerodynamics affiliated to the train and bridge, compared with a moving vehicle wind tunnel test and full-scale experiment. At present, the dynamic mesh and sliding mesh method are usually used to present the movement of the train in the simulation.…”

Vibration Suppression of Wind/Traffic/Bridge Coupled System Using Multiple Pounding Tuned Mass Dampers (MPTMD)

“…Since the TMD concept was first investigated by Frahm [6], much research has been carried out to examine its effectiveness for various dynamic load applications. Much of the previous research efforts were focused on optimizing the TMD parameters and suppressing the bridge vibration under wind or seismic loads [7,8,9,10,11,12,13,14,15]. However, we found few studies on applying TMDs to suppress bridge vibrations induced by combined wind and traffic loads [16,17].…”