Wind Climate Under the Demand of Island Runway Design

2018 ◽  
pp. 113-121 ◽  
Author(s):  
Chongwei Zheng ◽  
Chongyin Li ◽  
Hailang Wu ◽  
Min Wang
Keyword(s):  
Wind Climate

The Australian National Windbreaks Program: overview and summary of results

2002 ◽  
Vol 42 (6) ◽  
pp. 649 ◽  
Author(s):  
H. A. Cleugh ◽  
R. Prinsley ◽  
P. R. Bird ◽  
S. J. Brooks ◽  
P. S. Carberry ◽  
...  
Keyword(s):  
Growing Season ◽  
Climate Data ◽  
Financial Gain ◽  
Temperature And Humidity ◽  
Wind Climate ◽  
Wind Events ◽  
Differing Effect ◽  
Economic Analyses ◽  
The Individual ◽  
Variable Wind

This overview paper presents a description of the National Windbreaks Program (NWP) — its objectives, the main methods used to achieve these objectives and a summary of the key results. It draws these from the individual papers appearing in this special issue, which provide detailed descriptions and discussion about the specific research sites and research methods used, in addition to interpreting and discussing the results. The key findings were the following: (i) Two broad areas of crop and pasture response can be identified downwind of a porous windbreak: a zone of reduced yield associated with competition with the windbreak trees that extended from 1 H to 3 H, where H is the windbreak height, and a zone of unchanged or slightly increased yield stretching downwind to 10 H or 20 H. (ii) Averaged over the paddock, yield gains due to the effect of shelter on microclimate were smaller than expected — especially for cereals. Yield simulations conducted using the APSIM model and 20 years of historical climate data confirmed this result for longer periods and for other crop growing regions in Australia. Larger yield gains were simulated at locations where the latter part of the growing season was characterised by high atmospheric demand and a depleted soil water store. (iii) Economic analyses that account for the costs of establishing windbreaks, losses due to competition and yield gains as a result of shelter found that windbreaks will either lead to a small financial gain or be cost neutral. (iv) Part of the reason for the relatively small changes in yield measured at the field sites was the variable wind climate which meant that the crop was only sheltered for a small proportion of the growing season. In much of southern Australia, where the day-to-day and seasonal variability in wind direction is large, additional windbreaks planted around the paddock perimeter or as closely-spaced rows within the paddock will be needed to provide more consistent levels of shelter. (v) Protection from infrequent, high magnitude wind events that cause plant damage and soil erosion was observed to lead to the largest yield gains. The main forms of direct damage were sandblasting, which either buries or removes seedlings from the soil or damages the leaves and stems, and direct leaf tearing and stripping. (vi) A corollary to these findings is the differing effect that porous windbreaks have on the air temperature and humidity compared to wind. While winds are reduced in strength in a zone that extends from 5 H upwind to at least 25 H downwind of the windbreak, the effects of shelter on temperature and humidity are smaller and restricted mainly to the quiet zone. This means that fewer windbreaks are required to achieve reductions in wind damage than for altering the microclimate. (vii) The wind tunnel experiments illustrate the important aspects of windbreak structure that determine the airflow downwind, and subsequent microclimate changes, in winds oriented both perpendicular and obliquely to porous windbreaks. These results enable a series of guidelines to be forwarded for designing windbreaks for Australian agricultural systems.

CFD analysis of wind climate from human scale to urban scale

1999 ◽  
Vol 81 (1-3) ◽  
pp. 57-81 ◽  
Author(s):  
Shuzo Murakami ◽  
Ryozo Ooka ◽  
Akashi Mochida ◽  
Shinji Yoshida ◽  
Sangjin Kim
Keyword(s):  
Cfd Analysis ◽  
Human Scale ◽  
Wind Climate

scholarly journals Climate Change Induced Uncertainty of Wind Energy Potential for the Azov and Black Seas Coastal Zone

2020 ◽  
Author(s):  
V. P. Evstigneev ◽  
◽  
N. A. Lemeshko ◽  
V. A. Naumova ◽  
M. P. Evstigneev ◽  
...  
Keyword(s):  
Climate Change ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Power ◽  
Black Sea ◽  
Operating Time ◽  
Energy Output ◽  
Energy Potential ◽  
Wind Energy Potential ◽  
Wind Climate

The paper deals with assessing an impact of wind climate change on the wind energy potential of the Azov and Black Sea coast region. A lower estimate of operating time for wind power installation and a potential annual energy output for the region are given for the case of Vestas V117-4.2MW. Calculation has been performed of a long-term mean wind speed for two adjacent climatic periods (1954–1983 and 1984–2013) based on data from meteorological stations of the Black and Azov Sea region. The results show a decrease in wind speed at all meteorological stations except for Novorossiysk. The wind climate change is confirmed by comparing two adjoined 30-year periods and by estimating linear trends of the mean annual wind speed for the period 1954–2013, which are negative and significant for almost all meteorological stations in the region (α = 1 %). The trend values were estimated by the nonparametric method of robust linear smoothing using the Theil – Sen function. In the present study, the uncertainty of wind energy resource induced by a gradual wind climate change is estimated for perspective planning of this branch of energy sector. Despite the observed trends in the wind regime, average wind speeds in the Azov and Black Sea region are sufficient for planning the location of wind power plants.

scholarly journals A Wind Climate Dynamic Modeling and Control Using Weibull and Extreme Value Distribution System

2019 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Tim Chen ◽  
Alfred Hausladen ◽  
Jonathan Sstamler ◽  
Dneil Granger ◽  
Abu Hurayraasiv Khanand ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Distribution System ◽  
Extreme Value Distribution ◽  
Extreme Value ◽  
Value Distribution ◽  
Modeling And Control ◽  
Wind Climate ◽  
And Control ◽  
Climate Dynamic

scholarly journals Climate variations: Risk factor of commiting suicide

2011 ◽  
Vol 64 (3-4) ◽  
pp. 202-205 ◽  
Author(s):  
Caslav Milic ◽  
Sanja Kocic ◽  
Snezana Radovanovic
Keyword(s):  
Suicide Rate ◽  
Atmospheric Pressure ◽  
Early Summer ◽  
The Sun ◽  
Climate Factors ◽  
Climate Variations ◽  
Suicidal Risk ◽  
Wind Climate ◽  
Commit Suicide ◽  
Number Of Authors

Introduction. Recently there have been more and more attempts at getting into connection the frequency of suicide with climate factors, humidity changes, atmospheric pressure. A large number of authors agree that suicide has meteorological character and that weather can be a provoking factor in suicidal persons. Suicides happen most frequently when the weather is warm, stable, and sunny; then, when it is rainy, cloudy and with high humidity, and least frequently when the atmospheric pressure and temperature are decreased accompanied with wind. Climate variations and suicide. Men who commit suicide show a significant, positive connection with indicators of temperature and exposure to sun, and a significant, negative connection with indicators of humidity and rainfall. Women who commit suicide show a less significant connection with climate variations - indicators. Violent and non-violent suicide. Regarding violent and nonviolent suicide, it has been proved that violent suicide is affected by environmental temperature, sunny intervals, raise in temperature in the previous few weeks. Higher envi?ronmental temperature and increase in air temperature in the previous few weeks are the most significant climate factors influencing the violent suicide rate. In addition, each degree exceeding 18?C increases the violent suicide rate by 3.8-5%. Conclusion. The result of many investigations of the influence of climate factors on committing suicide is that the suicide incidence reaches its peak during early summer. Also, the sun radiation the day before suicidal event is significantly connected with the increased suicidal risk. There is a difference between sexes. If the sun were a trigger, men would have to be exposed to it for a longer time than women.

Importance of Shear in Site Assessment of Wind Turbine Fatigue Loads

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
René M. M. Slot ◽  
Lasse Svenningsen ◽  
John D. Sørensen ◽  
Morten L. Thøgersen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Structural Reliability ◽  
Turbine Blades ◽  
Structural Response ◽  
Fatigue Loading ◽  
Worst Case ◽  
Shear Model ◽  
Wind Climate

Wind turbines are subjected to fatigue loading during their entire lifetime due to the fluctuating excitation from the wind. To predict the fatigue damage, the design standard IEC 61400-1 describes how to parametrize an on-site specific wind climate using the wind speed, turbulence, wind shear, air density, and flow inclination. In this framework, shear is currently modeled by its mean value, accounting for neither its natural variance nor its wind speed dependence. This very simple model may lead to inaccurate fatigue assessment of wind turbine components, whose structural response is nonlinear with shear. Here we show how this is the case for flapwise bending of blades, where the current shear model leads to inaccurate and in worst case nonconservative fatigue assessments. Based on an optimization study, we suggest modeling shear as a wind speed dependent 60% quantile. Using measurements from almost one hundred sites, we document that the suggested model leads to accurate and consistent fatigue assessments of wind turbine blades, without compromising other main components such as the tower and the shaft. The proposed shear model is intended as a replacement to the mean shear, and should be used alongside the current IEC models for the remaining climate parameters. Given the large number of investigated sites, a basis for evaluating the uncertainty related to using a simplified statistical wind climate is provided. This can be used in further research when assessing the structural reliability of wind turbines by a probabilistic or semiprobabilistic approach.

Wind Climate Characteristics

2018 ◽  
pp. 17-34
Author(s):  
Chongwei Zheng ◽  
Ziniu Xiao ◽  
Wen Zhou ◽  
Xiaobin Chen ◽  
Xuan Chen
Keyword(s):  
Wind Climate
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