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>

scholarly journals The Effects of Spatial Configurations of Simulated Shrubs on Wind-proof Effectiveness

2021 ◽  
Author(s):  
Xia Pan ◽  
Zhenyi Wang ◽  
Yong Gao ◽  
Zhengcai Zhang ◽  
Xiaohong Dang ◽  
...  
Keyword(s):  
Control System ◽  
Wind Tunnel ◽  
Wind Velocity ◽  
Wind Erosion ◽  
Physical Interaction ◽  
Near Surface ◽  
Protection Effect ◽  
Surface Barriers ◽  
Spatial Configurations ◽  
Airflow Field

Maximizing the benefits of windbreaks requires a thorough understanding of the physical interaction between the wind and the barrier. In this experiment, a profiling set of Pitot tubes was used to measure the airflow field and wind velocity of simulated shrubs in a wind tunnel. The effects of form configurations and row spaces of simulated shrubs on wind-proof effectiveness were in-depth studied. We come to the following results: the weakening intensity of hemisphere-shaped and broom-shaped shrubs on wind velocity was mainly reflected below 2 cm in the root and 6-14 cm in the middle-upper, respectively, while the wind-proof effect of the spindle-shaped shrubs at the canopy (0.2-14 cm height) was the best. Besides, the simulated shrubs under 26.25 cm had the best protection effect on the wind velocity. Moreover, the designed windbreaks with Nitraria tangutorum, more effectively reduced the wind velocity among the windbreak compared to behind the windbreak. 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 a sheltered forest. The results could offer theoretical guidelines on how to arrange the windbreaks for preventing wind erosion in the most convenient and efficient ways.

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 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 tunnel simulation of an opencut tunnel airflow field along the Linhe-Ceke Railway, China

2019 ◽  
Vol 39 ◽  
pp. 66-76 ◽  
Author(s):  
Min Yan ◽  
Haibing Wang ◽  
Hejun Zuo ◽  
Gangtie Li
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Simulation ◽  
Airflow Field

scholarly journals Effect of wind on Svalbard reindeer fur insulation

Rangifer ◽  
2002 ◽  
Vol 22 (1) ◽  
pp. 93 ◽  
Author(s):  
Christine Cuyler ◽  
Nils A. Øritsland
Keyword(s):  
Heat Transfer ◽  
Wind Tunnel ◽  
Heat Loss ◽  
Wind Velocity ◽  
Rangifer Tarandus ◽  
Svalbard Reindeer ◽  
Significant Difference ◽  
Wind Velocities ◽  
Autumn And Winter

The heat transfer through Svalbard reindeer (Rangifer tarandus platyrhynchus) fur samples was studied with respect to wind velocity, season and animal age. A total of 33 dorsal fur sections were investigated using a wind tunnel. Insulation varied with season (calving, summer, autumn and winter). At zero wind velocity, fur insulation was significantly different between seasons for both calf and adult fur samples. At the same time, there was no significant difference between calf and adult insulation for the summer, autumn and winter seasons. Calf fur insulated as well as adult fur. Winter insulation of Svalbard reindeer was approximately 3 times that of summer. Increasing wind veloci¬ty increased heat loss, however, the increase was not dramatic. When wind coefficients (slope) of the heat transfer regression lines were compared, between season and between calf and adult, no significant differences were reported. All fur samples showed similar increases in heat transfer for wind velocities between 0 and 10 m.s-1. The conductance of winter fur of Svalbard reindeer was almost half that of caribou fur. Also, conductance was not as greatly influenced by wind as caribou fur

Effects of ridge height and spacing on the near-surface airflow field and on wind erosion of a sandy soil: Results of a wind tunnel study

2019 ◽  
Vol 186 ◽  
pp. 94-104 ◽  
Author(s):  
Wenru Jia ◽  
Chunlai Zhang ◽  
Xueyong Zou ◽  
Hong Cheng ◽  
Liqiang Kang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Sandy Soil ◽  
Wind Erosion ◽  
Near Surface ◽  
Ridge Height ◽  
Airflow Field ◽  
Wind Tunnel Study

scholarly journals Theoretical Analysis and Experimental Validation on Galloping of Iced Transmission Lines in a Moderating Airflow

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bing Huo ◽  
Xuliang Li ◽  
Fujiang Cui ◽  
Shuo Yang
Keyword(s):  
Wind Tunnel ◽  
Transmission Line ◽  
Wind Velocity ◽  
Transmission Lines ◽  
Damage Mechanism ◽  
Continuous Model ◽  
Vibrational Amplitude ◽  
Sudden Increase ◽  
Wind Field Model ◽  
Wind Velocities

Galloping of an iced transmission line subjected to a moderating airflow has been analysed in this study, and a new form of galloping is discovered both theoretically and experimentally. The partial differential equations of the iced transmission line are established based on the Hamilton theory. The Galerkin method is then applied on the continuous model, and a discrete model is derived along with its first two in-plane and torsional modes. A trapezoidal wind field model is built through the superposition of simple harmonic waves. The vibrational amplitude is generally observed to be more violent when the wind velocity decreases, except in the 2nd in-plane mode. Furthermore, the influence of the declining wind velocity rates on galloping is analysed using different postdecline wind velocities and the duration of the decline in wind velocities. Subsequently, an experiment has been carried out on a continuous model of an iced conductor in the wind tunnel dedicated for galloping. The first two in-plane modal profiles are observed, along with their response to the moderating airflow. Different declining rates of the wind velocity are also verified in the wind tunnel, which show good agreement with the results simulated by the mathematical model. The sudden increase in the galloping amplitude poses a significant threat to the transmission system, which also improves the damage mechanism associated with the galloping of a slender, a long structure with a noncircular cross-section.

A numerical approach for the assessment of crosswind effects on barrier-protected trains running on bridges

2021 ◽  
Author(s):  
Giuseppe Porpiglia ◽  
Paolo Schito ◽  
Tommaso Argentini ◽  
Alberto Zasso
Keyword(s):  
Wind Tunnel ◽  
Velocity Profile ◽  
Wind Velocity ◽  
Aerodynamic Force ◽  
Numerical Approach ◽  
Aerodynamic Performance ◽  
Vehicle Speed ◽  
Initial Condition ◽  
Cfd Analyses ◽  
Moving Train

<p>This paper introduces a new methodology to assess the influence of a windscreen on the crosswind performance of trains running on a bridge. Considering the difficulties encountered in both carrying out wind tunnel tests that consider the vehicle speed or complete CFD analyses, a simplified CFD approach is here discussed. Instead of simulating simultaneously the windscreen plus the moving train, the numerical problem is split into two parts: firstly, a simulation of the windshield alone is used to extract the perturbed velocity profile at the railway location; secondly, this profile used as an inlet condition for the wind velocity acting on an isolated train. The method is validated against a complete train plus windshield simulation in terms of pressure distribution and aerodynamic force coefficients on the train, and flow streamlines. This approach opens to the possibility of evaluating the aerodynamic performance of a vehicle on bridges considering bridge and vehicle as separated. Wind velocity profiles measured on the bridge during a wind tunnel campaign could be used as the initial condition for numerical simulations on vehicles.</p>

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