scholarly journals 2.5D Flexible Wind Sensor Using Differential Plate Capacitors

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3101
Author(s):  
Yu Wan ◽  
Zhenxiang Yi
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Parallel Plate ◽  
Electrode Array ◽  
Copper Electrode ◽  
Windward Side ◽  
Leeward Side ◽  
Electrode Layer ◽  
Young’S Moduli ◽  
Speed Up

In this paper, a novel 2.5-dimensional (2.5D) flexible wind sensor is proposed based on four differential plate capacitors. This design consists of a windward pillar, two electrode layers, and a support layer, which are all made of polydimethylsiloxane (PDMS) with different Young’s moduli. A 2 mm × 2 mm copper electrode array is located on each electrode layer, forming four parallel plate capacitors as the sensitive elements. The wind in the xy-plane tilts the windward pillar, decreasing two capacitances on the windward side and increasing two capacitances on the leeward side. The wind in the z-axis depresses the windward pillar, resulting in an increase of all four capacitances. Experiments demonstrate that this sensor can measure the wind speed up to 23.9 m/s and the wind direction over the full 360° range of the xy-plane. The sensitivities of wind speed are close to 4 fF·m−1·s and 3 fF·m−1·s in the xy-plane and z-axis, respectively.

scholarly journals Effect of windbreaks on wind speed reduction and soil protection against wind erosion

2017 ◽  
Vol 12 (No. 2) ◽  
pp. 128-135 ◽  
Author(s):  
D. Řeháček ◽  
T. Khel ◽  
J. Kučera ◽  
J. Vopravil ◽  
M. Petera
Keyword(s):  
Wind Speed ◽  
Wind Erosion ◽  
Statistical Significance ◽  
Polynomial Equation ◽  
Windward Side ◽  
Leeward Side ◽  
Soil Protection ◽  
Speed Reduction ◽  
Optical Porosity ◽  
Cultivated Plant

Windbreaks form efficient soil protection against wind erosion particularly at the time when soil cover is not protected by the cultivated plant vegetation cover. The objective of this research was to evaluate windbreaks efficiency in terms of wind speed reduction. Wind speed along the windbreaks was measured in the cadastral areas of Dobrovíz and Středokluky (Czech Republic, Central Europe). The measurement was carried out by 4 stations placed at windward side (1 station at the distance of 3 times the height of the windbreak) and at leeward side of the windbreak (3 stations at the distance of 3, 6, and 9 times the height of the windbreak). Each station contained 2 anemometers situated 0.5 and 1 m above surface. The character of windbreak was described by terrestrial photogrammetry method as the value of optical porosity from the photo documentation of the windbreak at the time of field measurement. A significant dependence between the value of optical porosity and efficiency of windbreak emerged from the results. The correlation coefficient between optical porosity and wind speed reduction was in the range of 0.842 to 0.936 (statistical significance more than 95%). A significant effect of windbreak on airflow reduction was proven on the leeward side of windbreak in a belt corresponding to approximately six times the height of the windbreaks depending on the optical porosity and it was expressed by a polynomial equation.  

scholarly journals Development and application of a street-level meteorology and pollutant tracking system (S-TRACK)

2021 ◽  
Author(s):  
Huan Zhang ◽  
Sunling Gong ◽  
Lei Zhang ◽  
Jianjun He ◽  
Yaqiang Wang ◽  
...  
Keyword(s):  
Air Pollution ◽  
Wind Speed ◽  
Line Source ◽  
Living Environment ◽  
Windward Side ◽  
Leeward Side ◽  
Street Level ◽  
Building Layout ◽  
Potential Impact ◽  
Traffic Source

Abstract. A multi-model simulation system for street level circulation and pollutant tracking (S-TRACK) has been developed by integrating the Weather Research and Forecasting (WRF), the Computational Fluid Dynamics (CFD) and the Flexible Particle (FLEXPART) models. The winter wind environmental characteristics and the potential impact of a traffic source on nearby sites (about 300 to 400 m) in Jinshui district of Zhengzhou, China are analyzed with the system. It is found that the existence of buildings complicates the structure of the wind fields. The wind speed inside the building block is smaller than the background wind speed due to the dragging effect of dense buildings. Ventilation is better when the dominant airflow is in the same direction as the building layout. Influenced by the building layout, local circulations show that the windward side of the building is mostly the divergence zone and the leeward side is mostly the convergence zone, which is more obvious for high buildings and influencing air pollution transport at the street-level. Using the traffic source (line source) on a road within a city block, the system was applied to investigate the potential impact of a line source on specific sites under the influence of the streel-level circulations. The potential contribution ratio was estimated by the method of residence time analysis and to a particular site found to vary with the height of the site with a peak not at the ground but on a certain height. The results of the study are helpful to understand the characteristics of wind environment and effect of traffic emissions in the area, which is important to improve urban living environment and control air pollution.

scholarly journals Influence of Wind and Humidity on Foraging Behavior of Olfactory Mesopredators

2011 ◽  
Vol 125 (2) ◽  
pp. 132 ◽  
Author(s):  
Rebekah E. Ruzicka ◽  
Michael R. Conover
Keyword(s):  
Wind Speed ◽  
Foraging Behavior ◽  
Wind Direction ◽  
Weather Conditions ◽  
Windward Side ◽  
Red Foxes ◽  
Predator Species ◽  
Wind Speeds ◽  
Mammalian Predators ◽  
Striped Skunks

Many mammalian predators rely on scents to locate prey and weather conditions that affect an odor plume (i.e., scents suspended in air) or depositional odor (i.e., scents laid on the ground) should affect predator foraging behavior. We predicted that wind speed, wind direction, and humidity would influence the foraging behavior of olfactory mesopredators. We tested these predictions by conducting spotlight surveys for foraging Red Foxes (Vulpes vulpes), Striped Skunks (Mephitis mephitis), and Raccoons (Procyon lotor) along the dike surrounding Willard Bay Reservoir in Willard, Utah, from August 2008 to August 2009. We recorded predator species, locations, numbers, and weather conditions at the time each predator was observed. While humidity had no effect on foraging, wind speed and direction were significant predictors of a predator's nightly foraging activity, with most predators observed when wind speeds were 2 to 4 m/s and winds were blowing perpendicularly over the dike the dike rather than parallel to the dike. Wind speed and direction also influenced where predators foraged on the dike, with predators being more likely to forage on the windward side of the dike when wind speeds were high enough to cause turbulence. We detected differences among predator species in their response to wind speed: Raccoons were more active than Striped Skunks and Red Foxes when the wind was calm and blowing parallel to the dike. Overall, our results indicate that these predator species alter their foraging behavior based on wind speed and wind direction. By foraging when winds were light and blowing perpendicularly over the dike, predators could likely enhance their ability to locate food using olfaction.

scholarly journals Effect of Environmental Wind on Performance of a 600MW Direct Air-cooled Unit Based on FLUENT

2019 ◽  
Vol 118 ◽  
pp. 02019
Author(s):  
Junfeng Xu ◽  
Taoying Wang ◽  
Minmin Zhao
Keyword(s):  
Heat Transfer ◽  
Wind Speed ◽  
Flow Field ◽  
Wind Direction ◽  
Heat Transfer Performance ◽  
Air Flow ◽  
Transfer Efficiency ◽  
Windward Side ◽  
Transfer Performance ◽  
Heat Transfer Efficiency

The external flow field of a 600MW air-cooled unit is numerically simulated based on FLUENT. The distribution law of air flow field of air-cooled unit under different wind speed and wind direction conditions is studied. The influence of wind speed and wind direction on the heat transfer performance of air-cooled unit is analyzed. Predict the exhaust pressure of direct air-cooled unit under the influence of environmental wind. The results show that in the +X direction environmental wind, the first row of air-cooled unit on the windward side is prone to backflow; in the +Y direction environmental wind, the first row of air-cooled unit on the windward side is prone to hot air recirculation. As the wind speed increases, the heat transfer efficiency of the air-cooled unit decreases. The dominant wind direction (WNW) environmental wind has the least impact on the heat transfer efficiency, and the furnace wind (+Y direction wind) has the greatest influence on the heat transfer efficiency. To improve the heat transfer performance of the air-cooled unit under windy conditions, it is necessary to narrow the range of the negative pressure zone below the air-cooled unit and increase the cooling air flow rate of the air-cooled unit.

scholarly journals Study on Heat Exchange of Different Ventilation Structures of Asynchronous Traction Motor for High Speed EMU

2019 ◽  
Vol 5 (2) ◽  
pp. 16-30
Author(s):  
Weili Li ◽  
Junci Cao ◽  
Dong Li ◽  
Zhigang Wu
Keyword(s):  
Temperature Distribution ◽  
Wind Speed ◽  
High Speed ◽  
Heat Dissipation ◽  
Windward Side ◽  
Maximum Temperature ◽  
Leeward Side ◽  
Stator Core ◽  
Traction Motor ◽  
Asynchronous Traction Motor

Background: Aiming at the problems of high local temperature and uneven temperature distribution in asynchronous traction motor of high-speed Electric Multiple Unit (EMU) when it is running. Aim: In this paper, the influence of ventilation system with different structure on temperature distribution is studied. Methods: Taking 600kW asynchronous traction motor as an example, the electromagnetic-fluid-temperature analysis model of the traction motor is established, and the temperature values of different positions in the motor are obtained. The accuracy of the calculation results is verified by comparing with the actual measurement. On this basis, by adjusting the structure of stator and rotor axial ventilation holes, the relationship between temperature distribution and fluid flow state in motor is studied. In addition, the influence of fluid incidence angle on fluid velocity and heat dissipation performance of motor is also studied, and the ventilation structure scheme with relative balance of axial and circumferential temperature in motor is found out, which provides a reference strategy for the design of temperature rise of motor with forced ventilation structure. Results: The wind speed near the intake side of stator teeth and rotor teeth groove is less than that far from the intake side. The flow distribution trend of rotor vent is similar to that of stator vent, but the air in the groove is affected by centrifugal force of rotor rotation, which makes the wind speed difference on the intake side larger than that on the outlet side. The stator winding and rotor guide bar are affected by wind temperature to reach the maximum temperature at the end of the outlet respectively. The stator core is higher at the windward side and the leeward side than the other parts of the motor. The heat dissipation effect at both ends is good. The highest temperature of the stator core appears near the leeward side.

Investigation on the drag effect of a rolling element confined in the cavity of a cylindrical roller bearing

2021 ◽  
pp. 135065012110260
Author(s):  
Wenjun Gao ◽  
Shuo Zhang ◽  
Xiaohang Li ◽  
Zhenxia Liu
Keyword(s):  
Open Space ◽  
Roller Bearing ◽  
Flow Characteristics ◽  
Experimental Tests ◽  
Windward Side ◽  
Leeward Side ◽  
Drag Effect ◽  
Rolling Element ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

In cylindrical roller bearings, the drag effect may be induced by the rolling element translating in a fluid environment of the bearing cavity. In this article, the computational fluid dynamics method and experimental tests are employed to analyse its flow characteristics and pressure distribution. The results indicate that the pressure difference between the windward side and the leeward side of the cylinder is raised in view of it blocking the flow field. Four whirl vortexes are formed in four outlets of two wedge-shaped areas between the front part of the cylindrical surface and adjacent walls for the cylinder of L/ D = 1.5 at Re = 4.5 × 103. Vortex shedding is found in the direction of cylinder axis at Re = 4.5 × 104. The relationship between drag coefficient and Reynolds number is illustrated, obviously higher than that of the two-dimensional cylinder in open space.

Movement of Large Convective Rainstorms in Relation to Winds Aloft

1958 ◽  
Vol 39 (3) ◽  
pp. 129-136 ◽  
Author(s):  
C. W. Newton ◽  
Sey Katz
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Rainfall Data ◽  
Squall Lines ◽  
Hourly Rainfall ◽  
The Difference ◽  
Strong Winds

By means of hourly rainfall data from the Hydroclimatic Network, the motions of large rainstorms, of the kind associated with squall lines, are examined in relation to the winds aloft. Very little correlation is found between the speed of movement of the rainstorms and the wind speed at any level, although the fastest moving storms were associated with strong winds aloft. Significant correlation is found between direction of motion of rainstorms, and wind direction at 700 mb or higher levels. On the average, the rainstorms move with an appreciable component toward right of the wind direction. The difference between these results, and those from other studies based on small precipitation areas, is ascribed to propagation. The mechanism involved is discussed briefly.

Air movement and heat loss from sheep. II. Thermal insulation of fleece in wind

1980 ◽  
Vol 209 (1175) ◽  
pp. 209-217 ◽  
Keyword(s):  
Thermal Diffusivity ◽  
Heat Loss ◽  
Thermal Insulation ◽  
General Relation ◽  
Windward Side ◽  
Leeward Side ◽  
Sensible Heat ◽  
Bulk Resistance ◽  
Air Movement ◽  
Dimensionless Constant

Penetration of an animal’s coat by wind reduces its thermal insulation and increases heat loss to the environment. From studies of the sensible heat loss from a life-sized model sheep covered with fleece, the average fleece resistance r¯ f (s cm -1 ) was related to windspeed u (m s -1 ) by 1/ r¯ f ( u ) = l/ r¯ f (0) + cu , where c is a dimensionless constant. As c is expected to be inversely proportional to coat depth Î , the more general relation k¯ ( u ) = k¯ (0) + c'u was evaluated, where k¯ = Î / r¯ f is the thermal diffusivity (cm 2 s -1 ) of the fleece and c' = cÎ is another constant (cm). The orientation of the model to the wind had little effect on the bulk resistance of the fleece, but the resistance on the windward side was substantially lower than on the leeward side.

scholarly journals Surface gas pollutants in Lhasa, a highland city of Tibet – current levels and pollution implications

2014 ◽  
Vol 14 (19) ◽  
pp. 10721-10730 ◽  
Author(s):  
L. Ran ◽  
W. L. Lin ◽  
Y. Z. Deji ◽  
B. La ◽  
P. M. Tsering ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Fossil Fuels ◽  
Trace Gases ◽  
Early Morning ◽  
Current Status ◽  
Urban Site ◽  
Large Variability ◽  
Mixing Ratios ◽  
Low Wind Speed

Abstract. Through several years of development, the city of Lhasa has become one of the most populated and urbanized areas on the highest plateau in the world. In the process of urbanization, current and potential air quality issues have been gradually concerned. To investigate the current status of air pollution in Lhasa, various gas pollutants including NOx, CO, SO2, and O3, were continuously measured from June 2012 to May 2013 at an urban site (29.40° N, 91.08° E, 3650 m a.s.l.). The seasonal variations of primary gas pollutants exhibited a peak from November to January with a large variability. High mixing ratios of primary trace gases almost exclusively occurred under low wind speed and showed no distinct dependence on wind direction, implying local urban emissions to be predominant. A comparison of NO2, CO, and SO2 mixing ratios in summer between 1998 and 2012 indicated a significant increase in emissions of these gas pollutants and a change in their intercorrelations, as a result of a substantial growth in the demand of energy consumption using fossil fuels instead of previously widely used biomass. The pronounced diurnal double peaks of primary trace gases in all seasons suggested automobile exhaust to be a major emission source in Lhasa. The secondary gas pollutant O3 displayed an average diurnal cycle of a shallow flat peak for about 4–5 h in the afternoon and a minimum in the early morning. Nighttime O3 was sometimes completely consumed by the high level of NOx. Seasonally, the variations of O3 mixing ratios displayed a low valley in winter and a peak in spring. In autumn and winter, transport largely contributed to the observed O3 mixing ratios, given its dependence on wind speed and wind direction, while in spring and summer photochemistry played an important role. A more efficient buildup of O3 mixing ratios in the morning and a higher peak in the afternoon was found in summer 2012 than in 1998. An enhancement in O3 mixing ratios would be expected in the future and more attention should be given to O3 photochemistry in response to increasing precursor emissions in this area.

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