scholarly journals Wind Tunnel Test on Local Wind Field around the Bridge Tower of a Truss Girder

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jingyu Zhang ◽  
Mingjin Zhang ◽  
Bing Huang ◽  
Yongle Li ◽  
Jiaxin Yu ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Field ◽  
Large Scale ◽  
Leeward Side ◽  
Local Wind ◽  
Height Range ◽  
Wind Barrier ◽  
Local Wind Field ◽  
Bridge Tower

The aerodynamic performance of vehicles on a bridge deck depends on the local wind field, especially in a region near a bridge tower. This study was carried out on a large-scale (1: 20.4) truss girder, and wind tunnel tests were performed to determine how the wind fields were affected by the bridge tower in the presence of different wind barriers. The wind barrier parameters significantly affect the wind field. Wind barriers should be sufficiently high to provide a wide protection range and have relatively small porosities to reduce the wind speed. The opening form of the wind barrier should also be considered, where a circular-holed form reduces the wind speed and turbulence more than a horizontal-slatted form. The wind field is affected by structures and bridge towers on the deck. A turning point in the wind speed occurs at a measurement point near the bridge tower, and this point gradually moves upward towards lanes on the leeward side of the bridge. The equivalent wind speed is significantly reduced over a four-meter height range because of shadowing from the bridge tower and the wind barrier.

Influence of the synoptic circulation on the local wind field in a coastal area of the Tyrrhenian Sea

2008 ◽  
Vol 1 ◽  
pp. 012049 ◽  
Author(s):  
G Mastrantonio ◽  
I Petenko ◽  
A Viola ◽  
S Argentini ◽  
L Coniglio ◽  
...  
Keyword(s):  
Coastal Area ◽  
Wind Field ◽  
Tyrrhenian Sea ◽  
Local Wind ◽  
Synoptic Circulation ◽  
Local Wind Field

Influence of elevated water levels on wind field characteristics at a bridge site

2019 ◽  
Vol 22 (7) ◽  
pp. 1783-1795 ◽  
Author(s):  
Hongmiao Jing ◽  
Haili Liao ◽  
Cunming Ma ◽  
Kejian Chen
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Water Level ◽  
Wind Field ◽  
Wind Profile ◽  
Water Levels ◽  
Bridge Engineering ◽  
Bridge Site ◽  
Bridge Girder ◽  
Elevated Water

The influence of elevated water levels on wind field characteristics at bridge sites owing to hydroelectric power stations plays an important role in bridge engineering, particularly in mountainous valley regions. To investigate this issue, a comparative experimental study, which uses a topographic model with two water level states for determining the influence on wind field characteristics at the proposed bridge site located in a mountainous valley area, was conducted in the XNJD-3 wind tunnel at Southwest Jiaotong University, Chengdu, PR China. The altitude difference between the two water level states was approximately 200 m, whereas uniform and D-type boundary layer air inflow conditions were adopted during the wind tunnel test, respectively. The wind speed at the bridge girder and profile of the 1/4, mid, and 3/4 spans were recorded during the experiment. The test results indicated that after the water level was raised, the mean wind speed (or speed-up factor) along the bridge girder decreased by approximately 10%, and the values of the wind profile also decreased. However, the wind profile curve shapes remained approximately unchanged, and the wind attack angle was significantly transformed by approximately 5° in certain locations of the bridge girder. Moreover, the variation in the water level had a negligible influence on the turbulence intensities, turbulence integral length scales, probability distribution of fluctuating wind components, and turbulent wind spectra along the bridge girder. Therefore, as the water level in the canyon rises, the wind field characteristics at the bridge site tend to be conducive to bridge safety. Therefore, long-span bridges located in mountainous valley areas should be designed appropriately according to the expected minimum water level of the river.

scholarly journals Wind Turbine Wake Modeling in Accelerating Wind Field: A Preliminary Study on a Two-Dimensional Hill

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 153 ◽  
Author(s):  
Omar M. A. M. Ibrahim ◽  
Shigeo Yoshida ◽  
Masahiro Hamasaki ◽  
Ao Takada
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Field ◽  
Complex Terrain ◽  
Wind Farm ◽  
Wind Tunnel Test ◽  
Two Dimensional ◽  
Preliminary Study ◽  
Wake Model

Complex terrain can influence wind turbine wakes and wind speed profiles in a wind farm. Consequently, predicting the performance of wind turbines and energy production over complex terrain is more difficult than it is over flat terrain. In this preliminary study, an engineering wake model, that considers acceleration on a two-dimensional hill, was developed based on the momentum theory. The model consists of the wake width and wake wind speed. The equation to calculate the rotor thrust, which is calculated by the wake wind speed profiles, was also formulated. Then, a wind-tunnel test was performed in simple flow conditions in order to investigate wake development over a two-dimensional hill. After this the wake model was compared with the wind-tunnel test, and the results obtained by using the new wake model were close to the wind-tunnel test results. Using the new wake model, it was possible to estimate the wake shrinkage in an accelerating two-dimensional wind field.

Sensitivity studies of the RegCM3 simulation of summer precipitation, temperature and local wind field in the Caribbean Region

2006 ◽  
Vol 86 (1-4) ◽  
pp. 5-22 ◽  
Author(s):  
D. Martínez-Castro ◽  
R. Porfirio da Rocha ◽  
A. Bezanilla-Morlot ◽  
L. Alvarez-Escudero ◽  
J. P. Reyes-Fernández ◽  
...  
Keyword(s):  
Wind Field ◽  
Summer Precipitation ◽  
Caribbean Region ◽  
Local Wind ◽  
Precipitation Temperature ◽  
Sensitivity Studies ◽  
The Caribbean ◽  
Local Wind Field

Wind tunnel tests on the characteristics of wind fields over a simplified gorge

2016 ◽  
Vol 20 (10) ◽  
pp. 1599-1611 ◽  
Author(s):  
Peng Hu ◽  
Yongle Li ◽  
Yan Han ◽  
CS Cai ◽  
Guoji Xu
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Direction ◽  
Wind Field ◽  
Small Range ◽  
Wind Fields ◽  
Wind Speeds ◽  
Mean Wind Speed ◽  
Wind Characteristics ◽  
The Mean

Characteristics of wind fields over the gorge or valley terrains are becoming more and more important to the structural wind engineering. However, the studies on this topic are very limited. To obtain the fundamental characteristics information about the wind fields over a typical gorge terrain, a V-shaped simplified gorge, which was abstracted from some real deep-cutting gorges where long-span bridges usually straddle, was introduced in the present wind tunnel studies. Then, the wind characteristics including the mean wind speed, turbulence intensity, integral length scale, and the wind power spectrum over the simplified gorge were studied in a simulated atmospheric boundary layer. Furthermore, the effects of the oncoming wind field type and oncoming wind direction on these wind characteristics were also investigated. The results show that compared with the oncoming wind, the wind speeds at the gorge center become larger, but the turbulence intensities and the longitudinal integral length scales become smaller. Generally, the wind fields over the gorge terrain can be approximately divided into two layers, that is, the gorge inner layer and the gorge outer layer. The different oncoming wind field types have remarkable effects on the mean wind speed ratios near the ground. When the angle between the oncoming wind and the axis of the gorge is in a certain small range, such as smaller than 10°, the wind fields are very close to those associated with the wind direction of 0°. However, when the angle is in a larger range, such as larger than 20°, the wind fields in the gorge will significantly change. The research conclusions can provide some references for civil engineering practices regarding the characteristics of wind fields over the real gorge terrains.

scholarly journals Aerodynamics of High-Sided Vehicles on Truss Girder Considering Sheltering Effect by Wind Tunnel Tests

2020 ◽  
Vol 15 (2) ◽  
pp. 66-88
Author(s):  
Jingyu Zhang ◽  
Mingjin Zhang ◽  
Yongle Li ◽  
Xu Huang ◽  
Zhong Zheng
Keyword(s):  
Large Scale ◽  
Sudden Change ◽  
Aerodynamic Characteristics ◽  
Leeward Side ◽  
Aerodynamic Coefficients ◽  
Test Vehicle ◽  
Aerodynamic Coefficient ◽  
Running Safety ◽  
Sheltering Effect ◽  
Bridge Tower

Aerodynamic characteristics of vehicles are directly related to their running safety, especially for the high-sided vehicles. In order to study the aerodynamic characteristics under multiple sheltering conditions, a complex large scale (1:20.4) truss model and three high-sided vehicles including articulated lorry, travelling bus and commercial van models with the same scale were built. The aerodynamic coefficients under various sheltering effects of wind barriers with different heights and porosities, bridge tower and the vehicle on the adjacent lane were measured. According to the results, wind barriers can effectively reduce wind speed behind them, thus decreasing the wind load acting on the vehicle, which causes the decrease of the aerodynamic response of all three vehicles. However, the influence at the leeward side is limited due to installation of central stabilizers. When the vehicle passes through the bridge tower, a sudden change occurs, the aerodynamic coefficients decrease and fluctuate in varying degrees, especially for the commercial van. When the vehicle moves in different lanes behind the bridge tower, the sheltering effect of the tower on the aerodynamic coefficient in Lane 1 is much greater than that in Lane 2. With regard to the interference between two vehicles on the adjacent lanes, the relative windward area between the test vehicle and the interference vehicle greatly affects the aerodynamics of the test vehicle.

scholarly journals Effect of working pressure at different spray nozzles on drift quantification in wind tunnel

2014 ◽  
Vol 34 (1) ◽  
pp. 66-73 ◽  
Author(s):  
Marco A. Gandolfo ◽  
Fernando K. Carvalho ◽  
Rodolfo G. Chechetto ◽  
Ulisses D. Gandolfo ◽  
Eder D. de Moraes
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Agricultural Production ◽  
Large Scale ◽  
Spray Drift ◽  
Application Technology ◽  
Working Pressure ◽  
Spray Solution ◽  
Tunnel Floor

Each year, there is an increase in pesticide consumption and in its importance of use in the large-scale agricultural production, being fundamental the knowledge of application technology to the activity success. The objective of the present study was to evaluate the influence of working pressure on the drift generated by different spray nozzles, assessed in wind tunnel. The treatments were composed of two spray nozzles AXI 110015 and AXI 11002 with pressure levels of 276 and 414 kPa. The spray solution was composed by water and NaCl at 10%. The applications were conducted at wind speed of 2.0 m s-1, being the drift collected at 5.0; 10.0 and 15.0 m away from the spray boom and at heights of 0.2; 0.4; 0.6; 0.8 e 1.0 m from the tunnel floor. To both spray nozzles, the greatest drift was collected at the smallest distance to the spray-boom and at the lowest height. The AXI 11002 nozzle gave a smaller drift relative to the AXI 110015 nozzle for the two tested pressures and for all the collection points. Regardless of the nozzle, a rise in the working pressure increases the spray drift percentage at all distances in the wind tunnel.

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