scholarly journals The Aerodynamic Characteristics of Road Vehicles Overtaking on Bridge Deck under Crosswinds

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ning Chen ◽  
Hongxin Sun ◽  
Xiuyong Wang ◽  
Longwei Zhang
Keyword(s):  
Bridge Deck ◽  
Aerodynamic Characteristics ◽  
Driving Safety ◽  
Aerodynamic Coefficients ◽  
Aerodynamic Forces ◽  
Road Vehicles ◽  
Box Girder ◽  
Cable Stayed Bridge ◽  
Aerodynamic Interference ◽  
Safety And Stability

The aerodynamic characteristics of road vehicles in windy environments are the prerequisites for the evaluation and prediction of the driving safety and stability. To investigate the aerodynamic characteristics of the overtaking vehicles on the bridge deck under the effects of crosswinds, models of a cable-stayed bridge with a typical flat box girder and road vehicles involving articulated lorry and commercial van with a scale of 1 : 40 were tested in the wind tunnel laboratory. A series of tests figured out the variation of the aerodynamic forces of road vehicles during the overtaking process after considering the aerodynamic interference between lorry and lorry, van and van, and lorry and van. Additionally, the influence of the lateral overtaking distance between the overtaking vehicles was regarded as well. The result reveals the upstream vehicle has a significant influence on the aerodynamic coefficients of the downstream vehicle, which have experienced dramatic fluctuations during the overtaking process, and the various shapes of the aerodynamic coefficients are highly dependent on it.

Aerodynamic Forces of Vehicles on the Bridge under Crosswinds

2013 ◽  
Vol 639-640 ◽  
pp. 1206-1209
Author(s):  
Y. Han ◽  
Steve C.S. Cai
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
Experimental Setup ◽  
Aerodynamic Coefficients ◽  
Aerodynamic Forces ◽  
Wind Turbulence ◽  
Aerodynamic Interference

In the present study, an experimental setup was made to measure the aerodynamic characteristics of vehicles on the bridge for different cases in a wind tunnel considering the aerodynamic interference. The influence of the wind turbulence, the vehicle interference, and the distance of vehicle from the windward edge of the deck on the aerodynamic coefficients of vehicles were investigated based on the experimental results. The measured results showed that the wind turbulence, the vehicle interference, and the vehicle distance from the windward edge significantly affected the aerodynamic coefficients of vehicles.

Cable Replacement of the Tacitus Cable Stayed Bridge

2018 ◽  
Author(s):  
Matti Kabos ◽  
Edwin Thie ◽  
Conor Lavery
Keyword(s):  
Bridge Deck ◽  
High Strength ◽  
Box Girder ◽  
Highway Infrastructure ◽  
Cable Stayed Bridge ◽  
Stay Cables ◽  
Main Cable ◽  
Steel Box Girder ◽  
Permanent Load ◽  
Steel Deck

As part of a major renovation programme of critical highway infrastructure in the Netherlands, the Tacitus Bridge at Ewijk, a 1055-metre-long orthotropic steel box girder deck of ten spans, with a main cable-stayed span of 270 metres, has undergone extensive strengthening and refurbishment. Due to the presence of micro-fissure defects identified in the existing lock coiled stay cables and an increase in permanent load on the bridge deck resulting from the addition of a high strength concrete overlay acting compositely with the orthotropic steel deck, it was concluded that the existing stay cables needed replacement. This paper presents the analytical approach developed to verify that the existing stay cables could be removed with no additional temporary supports and the use of advanced non-linear techniques to predict and monitor the performance of the bridge during each step of destressing the existing stay cables and of tensioning the new parallel strand cables.

Investigation of aerodynamic coefficients at Mach 6 over conical, hemispherical and flat-face spiked body

2017 ◽  
Vol 121 (1245) ◽  
pp. 1711-1732 ◽  
Author(s):  
R. Kalimuthu ◽  
R. C. Mehta ◽  
E. Rathakrishnan
Keyword(s):  
Flow Field ◽  
Blunt Body ◽  
Angle Of Attack ◽  
Separated Flow ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Geometrical Parameters ◽  
Aerodynamic Coefficients ◽  
Aerodynamic Forces ◽  
Flow Field Characteristics

ABSTRACTA forward spike attached to a blunt body significantly alters its flow field characteristics and influences aerodynamic characteristics at hypersonic flow due to formation of separated flow and re-circulation region around the spiked body. An experimental investigation was performed to measure aerodynamic forces for spikes blunt bodies with a conical, hemispherical and flat-face spike at Mach 6 and at an angle-of-attack range from 0° to 8° and length-to-diameterL/Dratio of spike varies from 0.5 to 2.0, whereLis the length of the spike andDis diameter of blunt body. The shape of the leading edge of the spiked blunt body reveals different types of flow field features in the formation of a shock wave, shear layer, flow separation, re-circulation region and re-attachment shock. They are analysed with the help of schlieren pictures. The shock distance ahead of the hemisphere and the flat-face spike is compared with the analytical solution and is showing satisfactory agreement with the schlieren pictures. The influence of geometrical parameters of the spike, the shape of the spike tip and angle-of-attack on the aerodynamic coefficients are investigated by measuring aerodynamic forces in a hypersonic wind tunnel. It is found that a maximum reduction of drag of about 77% was found for hemisphere spike ofL/D= 2.0 at zero angle-of-attack. Consideration for compensation of increased pitching moment is required to stabilise the aerodynamic forces.

scholarly journals The Effects of Aerodynamic Interference on the Aerodynamic Characteristics of a Twin-Box Girder

2021 ◽  
Vol 11 (20) ◽  
pp. 9517
Author(s):  
Buchen Wu ◽  
Geng Xue ◽  
Jie Feng ◽  
Shujin Laima
Keyword(s):  
Reynolds Number ◽  
Turbulence Intensity ◽  
Body Height ◽  
Flow Characteristics ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Incoming Flow ◽  
Aerodynamic Forces ◽  
Box Girder ◽  
The Mean

To investigate the aerodynamic characteristics of a twin-box girder in turbulent incoming flow, we carried out wind tunnel tests, including two aerodynamic interferences: leading body-height grid, and leading circular cylinder. In this study, the pressure distribution and the mean and fluctuating aerodynamic forces with the two interferences are compared with bare deck in detail to investigate the relationship between aerodynamic characteristics and the incoming flow characteristics (including Reynolds number and turbulence intensity). The experimental results reveal that, owing to the body-height flow characteristics around the deck interfered with by the body-height grid, the disturbed aerodynamic characteristics of the twin-box girder differ considerably from those of the bare twin-box girder. At the upstream girder, due to the vortex emerging from the body-height grid breaking the separation bubble, pressure plateaus in the upper and lower surface are eliminated. In addition, the turbulence generated by the body-height grid reduces the Reynolds number sensitivity of the twin-box girder. At a relatively high Reynolds number, the fluctuating forces are mainly dominated by turbulence intensity, and the time-averaged forces show almost no change under high turbulence intensity. At a low Reynolds number, the time-averaged forces change significantly with the turbulence intensity. Moreover, at a low Reynolds number, the wake of the leading cylinder effectively forces the boundary layer to transition to turbulence, which reduces the Reynolds number sensitivity of the mean aerodynamic forces and breaks the separation bubbles. Additionally, the fluctuating drag force and the fluctuating lift force are insensitive to the diameter and the spacing ratio.

Numerical Simulation on Aerodynamic Characteristics of Road Vehicles on Bridges under Cross Winds

2013 ◽  
Vol 774-776 ◽  
pp. 241-247
Author(s):  
Y. Han ◽  
S. Q. Shu ◽  
D. Tan
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Force ◽  
Aerodynamic Characteristics ◽  
Wind Loads ◽  
Aerodynamic Forces ◽  
Road Vehicles ◽  
Force Coefficients ◽  
The Road ◽  
Cfd Method

The aerodynamic force coefficients of road vehicles under wind loads depend on not only the shapes of vehicles but also those of infrastructures, such as a bridge. Therefore, study of the aerodynamic characteristics of road vehicles considering the interaction of aerodynamic forces between the road vehicles and bridge is necessary for predicting the performance of vehicle under wind loads properly. This paper studies aerodynamic characteristics of road vehicles when vehicles run on bridges under cross winds using the CFD method. The dependence of aerodynamic forces on vehicle speeds, the interaction of aerodynamic forces between the vehicles and bridges and the influence of the turbulence are investigated by different simulation cases.

Wind tunnel tests on the aerodynamic characteristics of vehicles on highway bridges

2020 ◽  
Vol 23 (13) ◽  
pp. 2882-2897
Author(s):  
Xuhui He ◽  
Fanrong Xue ◽  
Yunfeng Zou ◽  
Suren Chen ◽  
Yan Han ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Bluff Body ◽  
Aerodynamic Characteristics ◽  
Strong Wind ◽  
Aerodynamic Coefficients ◽  
Wind Tunnel Tests ◽  
Side Force ◽  
Wind Barrier ◽  
Aerodynamic Interference ◽  
Body Section

Accurately quantifying the aerodynamic forces acting on vehicles and long-span bridges is critical for assessing the safety of moving vehicles on bridges which are subjected to strong wind. It is necessary to consider the aerodynamic interference between vehicles and the bridge, especially for this with the bluff body section and wind barriers. However, very few investigations have been carried out to find aerodynamic coefficients of vehicles on a bridge with the bluff body section and considering the effect of wind barrier. This article therefore carried out wind tunnel tests to determine aerodynamic coefficients of container truck on a bridge with a π-cross section and wind barriers. The influence of vehicle position in different road lanes of the bridge deck and the aerodynamic interference between vehicles on the aerodynamic characteristics of the vehicle and the bridge are investigated. Different heights and ventilation ratios of wind barrier are taken into consideration to examine variations of aerodynamic coefficients with different wind barriers. Furthermore, the change mechanism in the aerodynamic coefficients of the vehicles is observed by analyzing the wind pressure distribution on the surface of the vehicles. The test results show that the different lane locations of the vehicle affect the aerodynamic coefficients significantly, as well as the aerodynamic interference between vehicles with transverse arrangement or longitudinal arrangement, especially for the side force coefficient. The existence of wind barrier reduces the side force coefficients of the vehicle remarkably. Such effects also vary with the ventilation ratio and height of wind barrier.

Experimental Research on Aerodynamic Characteristics of Bridge Deck at Extreme Attack Angles

2010 ◽  
Vol 163-167 ◽  
pp. 4104-4108
Author(s):  
Fu You Xu ◽  
Bin Bin Li ◽  
Cai Liang Huang ◽  
Zhe Zhang
Keyword(s):  
Bridge Deck ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Attack Angle ◽  
Potential Danger ◽  
Box Girder ◽  
Long Span ◽  
Detailed Explanation ◽  
Section Model ◽  
Bridge Security

Long-span flexible bridges are always challenged by fierce wind load, and the wind with extreme-attack-angle may be a potential danger to threaten the bridge security. The three-component coefficients at extreme attack angles of the section model of one flat streamlined box-girder and central slotted box-girder are investigated through the wind tunnel test, and the detailed explanation are made. The results show that lift and pitch coefficients change approximately linearly between stall angles, and the coefficients display significant nonlinearity and a certain pulsation phenomenon when the attack angle exceeds stall angles, and the stall angles should not be less than ±10° for the sake of the safety of bridges.

scholarly journals Wind tunnel measurement of aerodynamic characteristics of trains passing each other on a simply supported box girder bridge

2021 ◽  
Author(s):  
Xiaozhen Li ◽  
Yiling Tan ◽  
Xiaowei Qiu ◽  
Zhenhua Gong ◽  
Ming Wang
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Sudden Change ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Coefficients ◽  
Box Girder ◽  
Simply Supported ◽  
Box Girder Bridge ◽  
Girder Bridge ◽  
Yaw Angle

AbstractThe aerodynamic performance of high-speed trains passing each other was investigated on a simply supported box girder bridge, with a span of 32 m, under crosswinds. The bridge and train models, modeled at a geometric scale ratio of 1:30, were used to test the aerodynamic forces of the train, with the help of a designed moving test rig in the XNJD-3 wind tunnel. The effects of wind speed, train speed, and yaw angle on the aerodynamic coefficients of the train were analyzed. The static and moving model tests were compared to demonstrate how the movement of the train influences its aerodynamic characteristics. The results show that the sheltering effect introduced by trains passing each other can cause a sudden change in force on the leeward train, which is further influenced by the wind and running speeds. Detailed analyses related to the effect of wind and train speeds on the aerodynamic coefficients were conducted. The relationship between the change in aerodynamic coefficients and yaw angle was finally described by a series of proposed fitting formulas.

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