scholarly journals Characteristics of Wind Velocity and Temperature Change Near an Escarpment-Shaped Road Embankment

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Young-Moon Kim ◽  
Ki-Pyo You ◽  
Jang-Youl You
Keyword(s):  
Wind Tunnel ◽  
Temperature Change ◽  
Wind Velocity ◽  
Field Measurement ◽  
Wind Tunnel Test ◽  
Level Difference ◽  
Before And After ◽  
Wind Velocities ◽  
Large Level ◽  
Velocity Changes

Artificial structures such as embankments built during the construction of highways influence the surrounding airflow. Various types of damage can occur due to changes in the wind velocity and temperature around highway embankments. However, no study has accurately measured micrometeorological changes (wind velocity and temperature) due to embankments. This study conducted a wind tunnel test and field measurement to identify changes in wind velocity and temperature before and after the construction of embankments around roads. Changes in wind velocity around an embankment after its construction were found to be influenced by the surrounding wind velocity, wind angle, and the level difference and distance from the embankment. When the level difference from the embankment was large and the distance was up to 3H, the degree of wind velocity declines was found to be large. In changes in reference wind velocities around the embankment, wind velocity increases were not proportional to the rate at which wind velocities declined. The construction of the embankment influenced surrounding temperatures. The degree of temperature change was large in locations with large level differences from the embankment at daybreak and during evening hours when wind velocity changes were small.

scholarly journals Hypersonic Free Flight Investigation on Rudder Reflection of Aircraft

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 542
Author(s):  
Fei Xue ◽  
Yuchao Wang ◽  
Zenghui Jiang ◽  
Yinong Yang
Keyword(s):  
Wind Tunnel ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Model Matching ◽  
Free Flight ◽  
Control Effect ◽  
Time Curve ◽  
Hypersonic Wind Tunnel ◽  
Before And After ◽  
Ejection Mechanism

In order to study the control effect of the rudder surface of the hypersonic vehicle and the coupling dynamic characteristics of the rudder surface deflection and the flight attitude, a technical platform for the deflection and motion coupling of the aircraft rudder surface was designed. The platform ejection mechanism can launch the model into the wind tunnel flow field according to the preset attitude, and model can free flight without support interference. The innovative design of the model internal rudder partial system can guarantee the model to deflect the rudder surface in the free flight process, simulate the real steering process of the aircraft. By changing spring with different springs, the speed of the rudder surface can be changed. The dual optical path and image acquisition technology can capture the motion picture before and after the deflection of the rudder surface from two angles. After the image is matched by model matching, the six degrees of freedom parameter of the model can be changed with the time curve before and after the deflection of the rudder surface, and the area of the six freedom degree curve of the different state model is compared. In other words, the specific influence of dynamic rudder rotation on the motion of the model is known. The wind tunnel test of the model in the hypersonic wind tunnel of the 500 mm is carried out using this platform. The test results are highly repeatable, and the test platform technology is mature and reliable.

scholarly journals Effects of an Anti-wind Net on Wind Velocity Reduction by a Wind Tunnel Test and CFD

2011 ◽  
Vol 36 (5) ◽  
pp. 355-360 ◽  
Author(s):  
Sung-Hyun Yum ◽  
Seung-Hee Kang ◽  
Seoung-Hee Kim ◽  
Sang-Bong Lee ◽  
Min-Young Kim
Keyword(s):  
Wind Tunnel ◽  
Wind Velocity ◽  
Wind Tunnel Test ◽  
Velocity Reduction

A Wind Tunnel Simulation of Windproof Effectiveness of Simulated Shrubs with Different Spatial Configurations

2021 ◽  
Author(s):  
Xia Pan ◽  
Zhenyi Wang ◽  
Yong Gao ◽  
Xiaohong Dang
Keyword(s):  
Wind Tunnel ◽  
Wind Velocity ◽  
Optimized Design ◽  
Near Surface ◽  
Wind Tunnel Simulation ◽  
Spatial Configurations ◽  
Wind Velocities ◽  
Airflow Field ◽  
Row Space ◽  
Better Than

<p>A better understanding of the distribution of the airflow field and wind velocity around the simulated shrubs is essential to provide optimized design and maximize the efficiency of the windbreak forests. In this study, a profiling set of Pitot Tube was used to measure the airflow field and wind velocity of simulated shrubs by wind tunnel simulation. The effects of form configurations and row spaces of simulated shrubs on windproof effectiveness were in-depth studied. We come to the following results: The weakening strength to wind velocities of hemisphere-shaped and broom-shaped shrubs at 26.25 cm was mainly concentrated below 2 cm near the root and 6-14 cm in the middle-upper part, while the spindle-shaped shrubs were at 0.2-14 cm above the canopy, which meant the windproof effect of spindle-shaped shrubs was was better than that of hemisphere-shaped and broom-shaped. With the improvement of row spaces, the weakening height to wind velocities of the hemisphere-shaped shrubs at 35 cm was only concentrated below 2 cm near the root exclude for the 6-14 cm at 26.25 cm, which presented the hemisphere-shaped shrubs were not suitable for the layout of wide row space. Further, the form configurations of simulated shrubs had a stronger influence on wind velocity than row spaces. Moreover, the designed windbreaks with <em>Nitraria tangutorum</em>, which more effectively reduced the wind velocity among the windbreaks compared to behind the windbreaks. In the wind control system, the hemisphere-shaped windbreaks should be applied as near-surface barriers, and the windbreaks of broom-shaped and spindle-shaped can be used as shelterbelts above the near-surface. These analytical findings offer theoretical guidelines on how to arrange the windbreak forests for preventing wind erosion in the most convenient and efficient ways.</p>

The Structural Stability Analysis of a Container Crane According to the Boom Shape Using Wind Tunnel Test

2007 ◽  
Vol 347 ◽  
pp. 365-372 ◽  
Author(s):  
Seong Wook Lee ◽  
Tae Won Ahn ◽  
Dong Seop Han ◽  
Tae Hyung Kim ◽  
Geun Jo Han
Keyword(s):  
Wind Tunnel ◽  
Structural Stability ◽  
Wind Velocity ◽  
Wind Tunnel Test ◽  
Wind Load ◽  
Wind Resistance ◽  
Container Crane ◽  
Cross Section Area ◽  
Section Area ◽  
Overturning Moment

In this study we carried out to analyze the effect of wind load on the structural stability of a container crane according to the change of the boom shape using wind tunnel test and provided a container crane designer with data which can be used in a wind resistance design of a container crane assuming that a wind load at 75m/s wind velocity is applied on a container crane. Data acquisition conditions for this experiment were established in accordance with the similarity. The scale of a container crane dimension, wind velocity and time were chosen as 1/200, 1/13.3 and 1/15. And this experiment was implemented in an Eiffel type atmospheric boundary-layer wind tunnel with 11.52m2 cross-section area. Each directional drag and overturning moment coefficients were investigated.

scholarly journals Prediction of Wind Velocity to Raise Vortex-Induced Vibration through a Road-Rail Bridge with Truss-Shaped Girder

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Seungtaek Oh ◽  
Sung-il Seo ◽  
Hoyeop Lee ◽  
Hak-Eun Lee
Keyword(s):  
Wind Tunnel ◽  
Natural Frequency ◽  
Wind Velocity ◽  
Vortex Shedding ◽  
Natural Frequencies ◽  
Wind Tunnel Test ◽  
Resonance Phenomenon ◽  
Vortex Induced Vibration ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency

Vortex-induced vibration (VIV) of bridges, related to fluid-structure interaction and maintenance of bridge monitoring system, causes fatigue and serviceability problems due to aerodynamic instability at low wind velocity. Extensive studies on VIV have been performed by directly measuring the vortex shedding frequency and the wind velocity for indicating the largest girder displacement. However, previous studies have not investigated a prediction of wind velocity to raise VIV with a various natural frequency of the structure because most cases have been focused on the estimation of the wind velocity and peeling-off frequency by the mounting structure at the fixed position. In this paper, the method for predicting wind velocity to raise VIV is suggested with various natural frequencies on a road-rail bridge with truss-shaped girder. For this purpose, 12 cases of dynamic wind tunnel test with different natural frequencies are performed by the resonance phenomenon. As a result, it is reasonable to predict wind velocity to raise VIV with maximum RMS displacement due to dynamic wind tunnel tests. Furthermore, it is found that the natural frequency can be used instead of the vortex shedding frequency in order to predict the wind velocity on the dynamic wind tunnel test. Finally, curve fitting is performed to predict the wind velocity of the actual bridge. The result is shown that predicting the wind velocity at which VIV occurs can be appropriately estimated at arbitrary natural frequencies of the dynamic wind tunnel test due to the feature of Strouhal number determined by the shape of the cross section.

scholarly journals Wind Tunnel Test Investigation on Unsteady Aerodynamic Coefficients of Iced 4-Bundle Conductors

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Mengqi Cai ◽  
Linshu Zhou ◽  
Hang Lei ◽  
Hanjie Huang
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Critical Parameters ◽  
Torsional Motion ◽  
Aerodynamic Coefficients ◽  
Unsteady Aerodynamic ◽  
Wind Velocities ◽  
Aerodynamic Instability ◽  
Test Investigation

Iced conductor motion is induced by the aerodynamic instability of these conductors. The unsteady aerodynamic characteristics are different from the steady aerodynamic characteristics. The unsteady aerodynamic coefficients of typical iced conductors’ models under torsional motion are measured by the unsteady wind tunnel test. The unsteady aerodynamic coefficients of crescent-shape and sector-shape iced 4-bundle conductors under different torsional motion frequencies, wind velocities, and ice thicknesses are obtained. Wind test results show that there are significant differences between the unsteady and steady aerodynamic coefficients. The unsteady aerodynamic coefficients curve is a loop which is different from the steady aerodynamic coefficients. In addition, the obvious differences exist between unsteady aerodynamic coefficients of crescent-shape and sector-shape iced bundle conductors. Critical parameters, including torsional motion frequencies, wind velocity, ice shape, and ice thickness, have significant influences on unsteady aerodynamic coefficients. It shows that the wind tunnel experiment results are able to provide necessary data for the investigation of iced bundle conductor motion and their prevention techniques.

scholarly journals SOME EFFECTS OF WIND ON THE GROWTH OF WHITE CLOVER (TRIFOLIUM REPENS L.) SEEDLINGS

1975 ◽  
pp. 253-253
Author(s):  
J.S. Bircham
Keyword(s):  
Wind Tunnel ◽  
Wind Velocity ◽  
White Clover ◽  
Trifolium Repens ◽  
Stages Of Growth ◽  
Wind Velocities ◽  
Total Plant ◽  
Trifolium Repens L

THE EFFECTS of wind velocity on Trifolium repens L. cv. 'Grasslands Huia' white clover seedlings were examined in a wind tunnel. Three experiments were conducted, each at a different wind velocity, in which wind was applied to seedlings at three distinct stages of growth (cotyledons, unifoliate leaf and trifoliate Icaf) for three periods of time (two, four and six days). The wind velocities were 5.0, 7.5 and 10.0 m/s. In all experiments total plant, shoot and root dry weights and shoot/root ratios were determined after 28 days.

Wind effects on Shenzhen Zhuoyue Century Center: Field measurement and wind tunnel test

2017 ◽  
Vol 26 (13) ◽  
pp. e1376 ◽  
Author(s):  
Haoran Pan ◽  
Zhuangning Xie ◽  
An Xu ◽  
Li Zhang
Keyword(s):  
Wind Tunnel ◽  
Field Measurement ◽  
Wind Tunnel Test ◽  
Wind Effects
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