Adaptive Neuro-Fuzzy Methodology for Noise Assessment of Wind Turbine

Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.     

Variability in greenhouse gas footprints of the global wind farm fleet

While technological characteristics largely determine the greenhouse gas (GHG) emissions during the construction of a wind farm and meteorological circumstances the actual electricity production, a thorough analysis to quantify the GHG footprint variability (in g CO₂eq/kWh electricity produced) between wind farms is still lacking at the global scale. Here, we quantified the GHG footprint of 26,821 wind farms located across the globe, combining turbine-specific technological parameters, life-cycle inventory data, and location- and temporal-specific meteorological information. These wind farms represent 79% of the 651 global wind (GW) capacity installed in 2019. Our results indicate a median GHG footprint for global wind electricity of 10 g CO₂eq/kWh, ranging from 4 to 56 g CO₂eq/kWh (2.5th and 97.5th percentiles). Differences in the GHG footprint of wind farms are mainly explained by spatial variability in wind speed, followed by whether the wind farm is located onshore or offshore, the turbine diameter, and the number of turbines in a wind farm. We also provided a metamodel based on these four predictors for users to be able to easily obtain a first indication of GHG footprints of new wind farms considered. Our results can be used to compare the GHG footprint of wind farms to one another and to other sources of electricity in a location-specific manner.     

基于“风感”的紧凑型城市开放空间风环境实测和CFD模拟比对研究

城市开放空间的风场不仅影响微环境的"风感"舒适度还影响宏观尺度的城市气候。从景感生态学的角度出发,首先阐述"风感"的定义,总结了街道峡谷空间风场的基本规律和特点。运用Kestrel NK4500手持气象站对城市开放空间的风环境进行实测,采用CFD(Computational Fluid Dynamics)模拟软件Fluent 14.0对不含绿地的同一空间进行风环境模拟,通过两者的数据比对来研究紧凑型城市开放空间内绿地对行人高度风场的实际干扰程度。结果发现,紧凑型城市开放空间的"风感"受建筑和绿地空间布局的共同影响。当建筑高于绿地时,风场受建筑的控制;当林带高于建筑时,林带对风环境的影响程度受其疏密度影响。疏密度较高的常绿林带对风向和风速影响很大,而疏密度较低的林带会影响风速,对风向影响不大。影响风速的主要因素是空间围合所形成的空气域,相比实体、多孔介质,空气域对风的阻力要小的多。如铺装、草坪上方的通风廊道是影响行人高度层通风、导风的关键因素。紧凑型空间内的绿地在行人高度应保持通畅以保证通风,并通过建立平面和竖向上的通风、导风廊道体系,促进空气循环。     

基于CFD模拟的不同地形格局风场规律及其风感规划对策

近地表地形的风场受坡度坡向、地表形态和空间格局等地形要素的控制,从而影响人的"风感"体验,是人居环境的选址与布局需要考虑的重要因素。通过建立地形3D模型、划分网格、设定模拟工况,运用Fluent 14.0软件对不同山体地形坡度、形态和格局的风场进行CFD （Computational Fluid Dynamics）模拟。结果发现：（1）坡度在0.3以下对地形风场影响较小;当坡度大于0.5时,随坡度增大背风坡风影区逐渐增大,挡风效果更加明显;坡度大于0.7以后,随着风影区加大,回流涡旋更加明显。（2）风场受到周边地形形体的影响,尤其是迎风面和背风面截面变化率。迎风面截面变化率越大,风速变化越快;背风面截面变化越大,背风面的出现风影区和回流涡旋的几率越大。迎风面出现凹形迎风口会形成气体滞留区,而背风面凹形口后部会增加风影区和回流涡旋出现的几率。（3）不同地形格局对单个地形的风场具有强化和减弱效果。"三面环山"的相对封闭的地形格局有利于形成稳定的风场,并提高风感舒适度。在人居环境的风感营造和优化中,需要避开风感敏感区域,即风速激增区、回流涡旋区、无固定风向的强烈湍流区、气流不流通的静风区和气流死循环涡旋区等风感敏感区,并利用植被或者人工构筑物来消除敏感区或削弱这一影响。并根据不同的气候类型和城市特点进行选址、地形改造或者进行内部地形格局调整和优化,以提高风感舒适度。选择开放型地形格局和低坡度、平行风向的流线型地形能够加强通风,而塑造封闭性地形格局和垂直风向的陡坡地形能够减小风速。     

The effects of a wind farm on birds in a migration point: the Strait of Gibraltar

The interaction between birds and wind turbines is an important factor to consider when a wind farm is constructed. A wind farm and two control areas were studied in Tarifa (Andalusia Province, southern Spain, 30STF590000–30STE610950). Variables were studied along linear transects in each area and observations of flight were also recorded from fixed points in the wind farm. The main purpose of our research was to determine the impact and the degree of flight behavioural change in birds flights resulting from a wind farm. Soaring birds can detect the presence of the turbines because they change their flight direction when they fly near the turbines and their abundance did not seem to be affected. This is also supported by the low amount of dead birds we found in the whole study period in the wind farm area. More studies will be necessary after and before the construction of wind farms to assess changes in passerine populations. Windfarms do not appear to be more detrimental to birds than other man-made structures.     

The Potential Wind Power Resource in Australia: A New Perspective

Australia’s wind resource is considered to be very good, and the utilization of this renewable energy resource is increasing rapidly: wind power installed capacity increased by 35% from 2006 to 2011 and is predicted to account for over 12% of Australia’s electricity generation in 2030. Due to this growth in the utilization of the wind resource and the increasing importance of wind power in Australia’s energy mix, this study sets out to analyze and interpret the nature of Australia’s wind resources using robust metrics of the abundance, variability and intermittency of wind power density, and analyzes the variation of these characteristics with current and potential wind turbine hub heights. We also assess the extent to which wind intermittency, on hourly or greater timescales, can potentially be mitigated by the aggregation of geographically dispersed wind farms, and in so doing, lessen the severe impact on wind power economic viability of long lulls in wind and power generated. Our results suggest that over much of Australia, areas that have high wind intermittency coincide with large expanses in which the aggregation of turbine output does not mitigate variability. These areas are also geographically remote, some are disconnected from the east coast’s electricity grid and large population centers, which are factors that could decrease the potential economic viability of wind farms in these locations. However, on the eastern seaboard, even though the wind resource is weaker, it is less variable, much closer to large population centers, and there exists more potential to mitigate it’s intermittency through aggregation. This study forms a necessary precursor to the analysis of the impact of large-scale circulations and oscillations on the wind resource at the mesoscale.     

无瓣海桑和秋茄人工林的减风效应

以海南东寨港三江湾无瓣海桑和秋茄人工林为研究对象,观测红树林内距向海林缘50 m、地面以上2 m高处的风速、风向特征,研究红树林的减风效应.结果表明:无瓣海桑和秋茄人工林均对偏北方向由海向岸的风速有明显的减弱效应,林带内50 m处的平均风速减低85％以上,并且秋茄林的减风效应更显著.随着风速的增加,林分的减风效能呈先下降后平缓的趋势.当风速低于5m·s-1时,无瓣海桑人工林内50 m处的平均风速减低89.8％;当风速在lOm·s-1以上时,其风速减低率趋于稳定;当风速＞15 m·s-1时,平均风速减低58.9％ ～63.6％.与冷季相比,无瓣海桑人工林暖季的减风效应更显著.在台风等极端天气状况下,无瓣海桑人工林内50 m处的平均风速和极大风速分别减低59.4％和53.2％.     

新疆风力发电减碳效益全生命周期评估

风力发电减碳效益评估有助于从减碳角度更好制定能源发展相关政策。以风力资源总体丰富且亟需发展风力发电以实现能源系统脱碳的新疆为研究区,将生命周期方法与风力发电模型结合,在省、市级尺度分别评估了风力发电全生命周期的排放水平及发电效益,核算了风力发电相对于火力发电和光伏发电的减碳效益,有效弥补了传统生命周期评估中空间差异考虑不充分的问题。结果表明,风机全生命周期平均发电量为13.1×10⁷ kWh,风力发电全生命周期共排放3944.24 tCO₂-eq,通过材料处置回收和循环再利用可减少1424.79 tCO₂-eq。新疆发展风力发电具有低排放强度和高减碳效益的特点,与火电相比可减少97.44%排放,减碳效益平均可达906.72 gCO₂-eq/kWh,并且应优先布局在哈密、巴音郭楞蒙古自治州和北屯市;与光伏相比,减碳效益可分别达到43.85 gCO₂-eq/kWh(衰减率DR=1%)和169.84 gCO₂-eq/kWh(DR=3%),此情景下风电应主要部署在克孜勒苏柯尔克孜自治州、喀什和和田。在风电减碳效益较差地区如石河子市、铁门关市和双河市应考虑利用本地充足太阳能资源发展光伏发电。需注意风电的排放强度和减碳效益在局地小尺度评估中存在不确定性,获取更精细的结果仍需进一步评估。未来应大力发展新疆本地的风电产业,打造绿色供应链和加快发展处置回收技术以增加减碳效益。     

风速对蒙古栎阔叶床层失水过程的影响

研究蒙古栎阔叶床层在近似恒温湿条件下不同风速时的失水过程,分析了风速对床层失水系数的影响.结果表明: 风速对蒙古栎阔叶床层失水过程的影响与可燃物含水率有关.从较高含水率(>75%)到近平衡含水率的多个失水过程可划分为3个阶段:有风失水速率大于无风失水速率的初始阶段、有风失水速率小于无风失水速率的中间阶段、不同风速失水速率相近的结束阶段.风速的影响随床层含水率降低而下降.蒙古栎阔叶床层的失水系数受风速、密实度和两者交互作用的影响,其中,失水系数随风速以三次多项式近似单调增加.     

Multivariate statistical analysis of the response of the cockroach giant interneuron system to wind puffs

The cockroach Periplaneta Americana responds to wind puffs by turning from the source of the wind. This turning movement is thought to be initiated by sensory responses to the wind puff occurring on filiform haircells on the cerci. The responses on the haircells initiate responses on 14 giant interneurons that rapidly transfer the information about the puff from the abdomen to the thorax and head. This response, in turn, is thought to initiate the escape response on the cockroach. In this paper a multivariate statistical analysis of the response of the 14 giant interneurons to wind puffs from a variety of angles is considered. A temporal-spatial integration model is proposed for the neural processing units acting as terminators for the giant interneurons and it is shown that using appropriate spatial integration, the cockroach can accurately estimate the direction of a wind puff on the basis of the response seen on the giant interneurons. It is also shown that with appropriate spatial integration, wind puffs from the left can be discriminated from wind puffs from the right. The right-left discrimination method is shown to be robust against the loss of any single giant interneuron. In some cases several giant interneurons can be lost without losing the right-left discrimination ability.     

An evaluation of the wind chill factor: its development and applicability.

The wind chill factor has become a standard meteorologic term in cold climates. Meteorologic charts provide wind chill temperatures meant to represent the hypothetical air temperature that would, under conditions of no wind, effect the same heat loss from unclothed human skin as does the actual combination of air temperature and wind velocity. As this wind chill factor has social and economic significance, an investigation was conducted on the development of this factor and its applicability based on modern heat transfer principles. The currently used wind chill factor was found to be based on a primitive study conducted by the U.S. Antarctic Service over 50 years ago. The resultant equation for the wind chill temperature assumes an unrealistic constant skin temperature and utilizes heat transfer coefficients that differ markedly from those obtained from equations of modern convective heat transfer methods. The combined effect of these two factors is to overestimate the effect of a given wind velocity and to predict a wind chill temperature that is too low.     

Wind dispersal in freshwater wetlands: Knowledge for conservation and restoration

Questions: For wetland plants, dispersal by wind is often overlooked because dispersal by water is generally assumed to be the key dispersal process. This literature review addresses the role of seed dispersal by wind in wetlands. Why is wind dispersal relevant in wetlands? Which seeds are dispersed by wind and how far? And how can our understanding of wind dispersal be applied to wetland conservation and restoration? Methods: Literature review. Results and conclusions: Wind is a widely available seed dispersal vector in wetlands and can transport many seeds over long distances. Unlike water, wind can transport seeds in all directions and is therefore important for dispersal to upstream wetlands and to wetlands not connected by surface water flows. Wind dispersal transports seeds to a wider range of sites than water, and therefore reaches more sites but with lower seed densities. Many wetland plant species have adaptations to facilitate wind dispersal. Dispersal distances increase with decreasing falling velocity of seeds, increasing seed release height and selective release mechanisms. Depending on the adaptations, seeds may be dispersed by wind over many km or only a few m. The frequency of long‐distance wind dispersal events depends on these adaptations, the number of produced seeds, the structure of the surrounding vegetation, and the frequency of occurrence of suitable weather conditions. Humans reduce the frequency of successful long‐distance wind dispersal events in wetlands through wetland loss and fragmentation (which reduce the number and quality of seeds) and eutrophication (which changes the structure of the vegetation so that seed release into the wind flow becomes more difficult). This is yet another reason to focus on wetland conservation and restoration measures at increased population sizes, prevention of eutrophication, and the restoration of sites at short distances from seed sources.     

Towards a better model of the effect of prostrate vegetation cover on wind erosion

Vegetation cover is the key to controlling wind erosion. A brief review of wind erosion/cover models is outlined. Fryrear's (1985) soil cover (wheat stubble) model was evaluated against field wind tunnel results from far south-west N.S.W. Fryrear's equation over estimated the soil loss compared to field wind tunnel results.Fryrear's model failed to provide meaningful results at low cover levels with the soil loss ratio, SLR>1 for percent soil cover, % SC<6. A single parameter exponential model was fitted to the wind tunnel data which ensured that SLR did not exceed 1 for 100% SC. Even with this improvement, the exponential model has drawbacks.Results suggest that the SLR is sensitive to wind velocity and that SLR goes to 0 well before % SC=100. A method for approximating the threshold wind velocity required to initiate erosion for various cover levels is described. Using the recurrence interval for a prescribed wind velocity, the probability of erosion hazard for a field can be determined.It is the authors belief that the wind tunnel is underestimating the occurrence of wind erosion events in this study. Three reasons why the wind tunnel may be underestimating erosion events are given.     

不同土地利用方式下土壤风蚀主要影响因子研究——以内蒙古武川县为例

以内蒙古武川县为例,选取天然草场、旱作农田(马铃薯)和退耕人工灌木林3类农用地为研究对象,对影响土壤风蚀的气候、植被覆盖度、土壤特性等若干因子进行了野外实测、室内分析及风洞模拟试验.结果表明,降雨少、风大、风多、土壤质地粗糙以及冬春冻融交替作用造成土壤表层疏松干燥等原因,决定了春季是该地区土壤风蚀的易发期.植被覆盖度是影响土壤风蚀的重要因子.在冬春风蚀季节覆盖度高低依次为灌木地＞天然草地＞旱作农田,此时缺少地表覆盖物保护的旱作农田最易受到风蚀危害.土壤含水量是影响风蚀的另一个重要因子.通过风洞试验对土壤风蚀率与含水量的定量关系研究表明,土壤含水量越高,土壤启动风速越大,风蚀率越小.6%土壤含水量是旱作农田风蚀强度由强变弱的一个转折点.田间试验结果表明,不同土地利用方式下表层土壤含水量总体上表现为天然草地＞旱作农田＞灌木林.通过风洞试验对土壤水分和风速的定量化研究表明,土壤风蚀速率随风速的增大而增大,二者呈幂函数关系.在净风吹蚀的条件下,18 m·s^-1风速是风蚀强度急剧增加的一个转折点.     

How to float a wind turbine

Far-offshore wind turbines are attractive in view of harnessing high-speed winds and reducing impact on population. When the sea is hundreds of metres deep, drilling wind turbines down to the seabed is too expensive. Today??s bottom-mounted foundations could be replaced by floating platforms, which can minimise the lateral wave-loads acting on the wind turbine and reduce the foundation cost in deep water. Computer models capable of calculating the motion of a full floating wind turbine are at an early stage of development. An efficient strategy to minimise the computational cost is also lacking. This contribution highlights how the motion of a floating wind turbine, and its interaction with the ocean, can be predicted by means of computer-model simulations.     

Field measurements of wind speed and reconfiguration in Arundo donax (Poaceae) with estimates of drag forces

The giant reed (Arundo donax) is well known as a species that can withstand high wind loads without mechanical damage. To examine wind impact, profiles of vertical wind speeds in the plant's natural habitat (southern France) were measured at the edge and within a stand in the main wind direction. Wind speed was recorded simultaneously at five heights. For 75 measurements of within-canopy wind speed profiles, the attenuation coefficient was 4.4 ± 0.5, a value typical for plant stands with very dense canopies. Video recordings proved that A. donax becomes streamlined with increasing wind speed, reducing the projected surface area of leaves and stem. The total projected surface area is a function of wind speed and can be characterized by a second-order polynomial regression curve. For small wind velocities up to 1 m/s, the calculated drag force is proportional to the square of the wind speed. However, when A. donax plants are subjected to higher wind speeds (1.5-10 m/s), the drag force becomes directly proportional to the wind speed. Streamlining is a potentially important adaptation for withstanding high wind loads, especially for individual plants and plants at the edge of stands, whereas in dense stands streamlining probably plays a minor role.     

Research on the Risk Level of Landfall Typhoons in Zhejiang,China

Zhejiang Province, as a major province of economic strength in China, has economically well-developed coastal areas, which are heavily damaged during landfall typhoons. In this paper, typhoons that could cause serious damages to Zhejiang Province will be labeled as “disastrous typhoons,” and the corresponding wind velocities will be labeled as “disastrous wind velocities.” It is suggested that typhoons exceeding certain threshold-values be selected as samples for calculation, and this method is called threshold-value sampling. According to the typhoon measurement data and by using the P-III distribution function, the disastrous wind velocity of certain recurrence interval in typhoon-resistant and engineering design projects was calculated. The calculation results show that the disastrous wind velocity of the largest landfall typhoon of coastal areas for the next 10 years is 41.8 m/s, the disastrous wind velocity in the next 50 years is 49.7 m/s, and 52.9 m/s in the next 100 years. It can be seen at the same time that the wind velocity calculated by the P-III distribution model is more similar to the actual conditions compared to the wind velocity calculated by the Weibull distribution model. This method is conceptually clear, easy to use, and generates ideal results.     

Wind effects on habitat distributions of wind-dispersed invasive plants across different biomes on a global scale: Assessment using six species

A number of widespread invasive plants are wind-dispersed, and wind may facilitate their dispersal and migration over a large distance. While wind is an important factor for seed dispersal and pollination, few studies have examined its potential to affect the habitat distribution of invasive plants over large spatial scales. We selected six of the world's worst invasive plants with wind-driving seed dispersal and pollination, and used wind speed as an indicator of wind. Environmental niche modelling was used to quantify the effects of wind on the habitat distribution of these invasive plants on a global scale and across 14 biomes. Wind had a negative effect on the habitat distribution of invasive plants in tropical and subtropical moist biomes, and a positive effect in Temperate Conifer Forests, Boreal Forests/Taiga, Temperate Grasslands, Savannas and Shrublands, and Montane Grasslands and Shrublands. We concluded that wind affected the habitat distribution of wind-dispersed invasive plants over a large scale, and this effect varied across different biomes. Thus, wind speed and biomes should be used as global monitoring indicators of invasion by wind-dispersed plants and wind speed variables should be included in the projection of habitat distributions of such invasive species when using ENM.     

森林的风/雪灾害研究综述

风／雪灾害不仪极大影响木材生产,同时对森林生态系统的稳定性也造成很大影响。森林风／雪危害的主要类型有树干弯曲、干(冠)折、掘根以及后续危害等;其发生主要依赖于气象条件、立地因子、树木和林分特征及其之间的相互作用。其中．林木尖削度(胸径／树高)和林分结构特征(树种、组成、密度等)是控制树木和林分对风／雪荷载抵抗的主要特征量。因此．通过造林、调整林分结构．加强林分管理如间伐、施肥等措施一直是用来减少林木的风／雪灾害的主要措施。另外．林木或林分发生风／雪害的模型分析研究也取得了很大进展,但由于森林风／雪害受诸如地形、天气等多种因素影响、目前所建立的模型系统在实际应用中普适性较芹。通过综述以往研究结果认为：在气象和立地条件难以控制的情况下．通过改变可控因子林分结构来减少森林风／雪害是可行的。因此．研究如何加强森林经营管理,尤其是不同形式的间伐技术和不同处理的造林措施与风／雪灾害发生的关系、如何增加林木和林分抵抗风／雪灾害的能力等是今后该研究领域的重点和难点。与此同时．应加强风／雪灾害危险率评估研究．进而对森林进行风／雪灾害危险率管理;并注重对受灾前后林地内生态效应的研究,以便为灾后的森林经营管理和调控提供坚实的理论依据。     

rWind: download,edit and include wind data in ecological and evolutionary analysis

1) Wind connectivity has been identified as a key factor driving many biological processes. 2) Existing software available for managing wind data are often overly complex for studying many ecological processes and cannot be incorporated into a broad framework. 3) Here we present rWind, an R language package to download and manage surface wind data from the Global Forecasting System and to compute wind connectivity between locations. 4) Data obtained with rWind can be used in a general framework for analysis of biological processes to develop hypotheses about the role of wind in driving ecological and evolutionary patterns.