Strong wind characteristics and turbulence

2020 ◽  
pp. 77-116
Author(s):  
John D. Holmes ◽  
Seifu A. Bekele
Keyword(s):  
Strong Wind ◽  
Wind Characteristics

scholarly journals Typhoon Type Index: A New Index for Understanding the Rain or Wind Characteristics of Typhoons and Its Application to Agricultural Losses and Crop Vulnerability

2020 ◽  
Vol 59 (5) ◽  
pp. 973-989
Author(s):  
Yuan-Chien Lin ◽  
Wen-Hsin Wang ◽  
Chun-Yeh Lai ◽  
Yong-Qing Lin
Keyword(s):  
Heavy Rainfall ◽  
Leafy Vegetables ◽  
General Situation ◽  
Strong Wind ◽  
Novel Approach ◽  
Bamboo Shoots ◽  
Typhoon Intensity ◽  
Wind Characteristics ◽  
Strong Winds ◽  
Different Characteristics

AbstractHeavy rainfall and strong wind are the two main sources of disasters that are caused by tropical cyclones (TCs), and typhoons with different characteristics may induce different agricultural losses. Traditionally, the classification of typhoon intensity has not considered the amount of rainfall. Here, we propose a novel approach to calculate the typhoon type index (TTI). A positive TTI represents a “wind type” typhoon, where the overall damage in a certain area from TCs is dominated by strong wind. On the other hand, a negative TTI represents a “rain type” typhoon, where the overall damage in a certain area from TCs is dominated by heavy rainfall. From the TTI, the vulnerability of crop losses from different types of typhoons can be compared and explored. For example, Typhoon Kalmaegi (2008) was classified as a rain-type typhoon (TTI = −1.22). The most affected crops were oriental melons and leafy vegetables. On the contrary, Typhoon Soudelor (2015) was classified as a significant wind-type typhoon in most of Taiwan (TTI = 1.83), and the damaged crops were mainly bananas, bamboo shoots, pomelos, and other crops that are easily blown off by strong winds. Through the method that is proposed in this study, we can understand the characteristics of each typhoon that deviate from the general situation and explore the damages that are mainly caused by strong winds or heavy rainfall at different locations. This approach can provide very useful information that is important for the disaster analysis of different agricultural products.

Wind Energy Potential in Taiwan

2013 ◽  
Vol 284-287 ◽  
pp. 1062-1066 ◽  
Author(s):  
Tsai Hsiang Chen ◽  
Van Tan Tran ◽  
Nien Che Yang ◽  
Ting Yen Hsieh
Keyword(s):  
Wind Energy ◽  
Roughness Length ◽  
Strong Wind ◽  
Energy Potential ◽  
Distribution Method ◽  
North East ◽  
Global Vision ◽  
Wind Energy Potential ◽  
Wind Characteristics ◽  
Weak Wind

The purpose of this paper is to contribute the database to users of wind power in Taiwan. The study analyzes 12 stations in Taiwan. The data were collected during the period 2001-2010. The Weibull distribution method was used to analyze wind characteristics and wind energy potential in the different site and height as well. The results show that the wind speed at the height 100 m and roughness length 0.1 m in Taiwan between 1.7 m/s and 4.3 m/s, and the power density from 5 W/m2 to 75 W/m2. Taipei is the windy place, while Taichung is the less. The direction of the wind most commonly comes from north-east. The wind energy varies depend on season, strong wind in spring and winter, while weak wind in autumn and summer. The results obtained contribute to a global vision of the wind energy potential and the windy areas in Taiwan.

Whole Process Wind Characteristics Field Measurements of a Strong Wind

2011 ◽  
Vol 243-249 ◽  
pp. 5094-5100 ◽  
Author(s):  
Ke Yang ◽  
Wen Hai Shi ◽  
Zheng Nong Li
Keyword(s):  
Wind Speed ◽  
Turbulence Intensity ◽  
Field Measurements ◽  
Integral Length Scale ◽  
Length Scale ◽  
Strong Wind ◽  
Gust Factor ◽  
Mean Wind Speed ◽  
Wind Characteristics ◽  
The Mean

This paper presents field measurement results of boundary layer wind characteristics over typical open country during the passages of typhoon Fung-wong passed by Wenzhou in July 2008. The field data such as wind speed and wind direction were measured from two propeller anemometers placed at the height of about 30m. The measured wind data are analyzed to obtain the information on mean wind speed and direction, turbulence intensity, gust factor, turbulence integral length scale and spectra of wind speed fluctuations. The results clearly demonstrate that the turbulence intensity and gust factor of typhoon Fung-wong are larger than normal, and there is a tendency for the turbulence intensities to decrease with the increase of the mean wind speed, however, there is another tendency for the turbulence integral length scale to increase with the increase of the mean wind speed. The power spectral densities of fluctuating wind speed in longitudinal and lateral directions obtained from the measured wind speed data roughly fit with Von Karman spectra. The results presented in this paper are expected to be of use to researchers and engineers involved in design of low-rise buildings.

Buffeting response of a composite cable-stayed bridge in a trumpet-shaped mountain pass

2019 ◽  
Vol 23 (3) ◽  
pp. 510-522
Author(s):  
Zheng-feng Shen ◽  
Jia-wu Li ◽  
Guang-zhong Gao ◽  
Xiao-feng Xue
Keyword(s):  
Wind Speed ◽  
Mountain Pass ◽  
Strong Wind ◽  
Wind Rose ◽  
Integral Scale ◽  
Buffeting Response ◽  
Cable Stayed Bridge ◽  
Mean Wind Speed ◽  
Scatter Plots ◽  
Wind Characteristics

Previous research showed that wind characteristics were influenced by terrain. To accurately calculate the wind-induced bridge response, this article presented a comprehensive investigation of the wind characteristics of a trumpet-shaped mountain pass by long-term monitoring. Basic strong wind characteristics such as the wind rose, turbulence intensities, turbulence length scales, turbulence spectra and normalized cross-spectrum were discussed using 10 min intervals. Due to the different types of terrain on the two sides of the bridge site, this article attempted to reflect the influence of the terrain on the wind characteristics in different wind directions. The scatter plots of wind characteristics were presented directly on the terrain map. The effects of the turbulence characteristics, mean wind speed and aerodynamic admittance function on buffeting response of the composite cable-stayed bridge were discussed by the multimode coupled frequency domain. The results show that the wind profile is extremely twisted. The larger turbulent integral scale and the lower turbulence intensity appear in the direction along the river. The effect of the mean wind speed on the buffeting response is greater than that of the fluctuating wind characteristics. The aerodynamic admittance function proposed by Holmes has the largest reduction in buffeting response.

scholarly journals Strong Wind Characteristics and Buffeting Response of a Cable-Stayed Bridge under Construction

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1228 ◽  
Author(s):  
Lei Yan ◽  
Lei Ren ◽  
Xuhui He ◽  
Siying Lu ◽  
Hui Guo ◽  
...  
Keyword(s):  
Field Measurements ◽  
Element Model ◽  
Vertical Acceleration ◽  
Strong Wind ◽  
Buffeting Response ◽  
Cable Stayed Bridge ◽  
Wind Characteristics ◽  
Strong Winds ◽  
Under Construction ◽  
Turbulence Parameters

This study carries out a detailed full-scale investigation on the strong wind characteristics at a cable-stayed bridge site and associated buffeting response of the bridge structure during construction, using a field monitoring system. It is found that the wind turbulence parameters during the typhoon and monsoon conditions share a considerable amount of similarity, and they can be described as the input turbulence parameters for the current wind-induced vibration theory. While the longitudinal turbulence integral scales are consistent with those in regional structural codes, the turbulence intensities and gust factors are less than the recommended values. The wind spectra obtained via the field measurements can be well approximated by the von Karman spectra. For the buffeting response of the bridge under strong winds, its vertical acceleration responses at the extreme single-cantilever state are significantly larger than those in the horizontal direction and the increasing tendencies with mean wind velocities are also different from each other. The identified frequencies of the bridge are utilized to validate its finite element model (FEM), and these field-measurement acceleration results are compared with those from the FEM-based numerical buffeting analysis with measured turbulence parameters.

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