Local Wind Characteristics Research Articles

Numerical Investigation of Wind Flow and Speedup Effect at a Towering Peak Extending out of a Steep Mountainside: Implications for Landscape Platforms

Wind flow over complex terrain is strongly influenced by the topographical features of the region, resulting in unpredictable local wind characteristics. This paper employs numerical simulation to study the wind flow at a towering peak extending out of a steep mountainside and the wind-induced effect on onsite landscape platforms. First, the wind flow from seven different directions is explored via 3D numerical simulations, and the wind load distribution on the platforms is highlighted. Second, a 2D numerical simulation is conducted to evaluate the wind speedup effect at the side peak, examining the influence of the side peak height and the mountainside steepness on the wind speedup factor. The numerical simulations presented in this research were validated by replicating a published numerical and experimental study. The results illustrate the amplifying and blocking effects of the surrounding topography, yielding unpredictable and nonuniform wind pressure distribution on the platforms. The presence of the side peak leads to a significant increase in the speedup factor, and the side peak height and the mountainside steepness have a moderate influence on the value of the speedup factor. Additionally, the speedup factor obtained from this study varies significantly, especially near the surface, from the recommendations of several wind load standards. Consequently, the impact of the local terrain and the wind speedup effect must be thoroughly assessed to ensure the structural integrity of structures installed at a similar topography.

Effect of built form on local wind characteristics, a case of tropical savanna climate in India

Passive techniques play a substantial role in regulating the indoor environmental quality of a building, especially in the tropics. Proper air movement is necessary for warm and humid indoors by utilising the local wind pattern. Many factors influence and alter the wind character of a region. Any built form has a significant influence on the wind and vice versa. This research extensively studies the effects of wind when it encounters different built and unbuilt spaces of an office building in India’s tropical savanna climate. Applications such as Building Information Modelling (Autodesk Revit) and Computational Fluid Dynamics simulation (Autodesk CFD) are used for analysis. The impacts on the local wind character at chosen wind path timings are studied in detail to arrive at the conclusions. Various effects like wind acceleration, corner jetting, channelling, funnelling, windbreak and cumulative effects are observed as occurring due to the influence of the building’s form on the local wind. These effects increased the wind velocity from 10kmph up to 19kmph and decreased up to 6kmph. The study concludes by arriving at several considerations while developing built forms that help to reduce negative impacts and improve positive impacts on aspects like aerodynamics, user comfort, impact on surroundings, the microclimate and structural wind loads.

The importance of grain‐related shear velocity in predicting multi‐monthly dune growth

AbstractThis study assesses the accuracy of the aeolian transport model proposed by van Rijn and Strypsteen in 2020 in predicting sediment transport rates for dune growth, with a focus on the importance of grain‐related shear velocity. A 9‐month dataset of local and regional wind characteristics and dune growth from a new artificial dune with planted marram grass in an environment with minor supply limitations was analysed. The study site is located in Oosteroever, Belgium. The results revealed that utilizing local measured overall shear velocities resulted in significant overprediction of dune volume changes. Incorporating sub‐models for grain‐related bed roughness and shear velocity improved the predictions of dune growth drastically with high statistical results (r2 = 0.98 and RMSE = 0.64 m3/m). The primary driver contributing to dune growth at the study site was due to oblique onshore moderate winds of 10 m/s, as revealed from a frequency‐magnitude analysis. The model could be used with either local wind measurements or regional data transformed to local beach conditions. The study highlights the importance of considering grain‐related shear velocity in future studies to improve the prediction of sand transport rates and enhance our understanding of dune evolution.

Categorization of High‐Wind Events and Their Contribution to the Seasonal Breakdown of Stratification on the Southern New England Shelf

AbstractHigh‐wind events predominantly cause the rapid breakdown of seasonal stratification on the continental shelf by the end of October. In particular the timing of events leads to considerable interannual variability in the stratification breakdown with a standard deviation of 15 days. Although previous studies have shown how coastal stratification depends on local wind‐forcing characteristics, the locally observed ocean forcing has not yet been linked to regional atmospheric weather patterns that determine the local wind characteristics. Establishing such a connection is a necessary first step toward examining how an altered atmospheric forcing due to climate change affects coastal ocean conditions. Here, we propose a categorization scheme for high‐wind events that links atmospheric forcing patterns with changes in stratification. We apply the scheme to the Southern New England shelf utilizing observations from the Ocean Observatories Initiative Coastal Pioneer Array (2015–2022). Impactful wind forcing patterns occur predominantly during early fall, have strong downwelling‐favorable winds, and are primarily of two types: (a) Cyclonic storms that propagate south of the continental shelf causing anticyclonically rotating winds, and (b) persistent large‐scale high‐pressure systems over East Canada causing steady north‐easterly winds. These patterns are associated with opposite temperature and salinity contributions to destratification, implying differences in the dominant processes driving ocean mixing based on a high‐wind pattern's overall strength and wind direction steadiness. The high‐wind event categorization scheme allows a transition from solely focusing on local wind forcing to considering realistic atmospheric weather patterns when investigating their impact on stratification in the coastal ocean.

The Use of Local Wind Simulation in Healthcare Facilities for Disease Control

Ventilation and air circulation are essential elements in healthcare facilities. Moreover, good ventilation helps to dilute odour pollutants and control the spread of the disease. This air circulation generally uses mechanical ventilation, whereas the use of natural ventilation is encouraged by the Indonesian Ministry of Health and the World Health Organization due to its affordability and sustainability considerations. Therefore, this paper aims to study the optimal building composition for health facilities using natural ventilation. There are two parts of the discussion in this manuscript. The first part is to study the building shape based on local wind characteristics. The second part is to determine the layout of the interior, adapting to the prevailing wind and its function. The research approach uses venturi theory, solar atrium and cross-ventilation, which is simulated through several computer simulations. The result showed that by orchestrating the building composition and layout in a specific way, natural ventilation could remove disease particles and provide better air circulation. These findings can be a new discussion in the planning and design of health facilities due to natural ventilation.

Evaluation of the near-surface wind field over the Adriatic region: local wind characteristics in the convection-permitting model ensemble

We present the first evaluation of the wind field from the ensemble of kilometer-scale simulations from the CORDEX-Flagship Pilot Study on convection, with focus on the Adriatic region. Kilometer-scale climate models, also known as convection-permitting models (CPMs), produce a good representation of small-scale topographic features and consequently a more detailed depiction of dynamical and thermal circulations. These enable a reliable view of climate characteristics of the wind field, especially in coastal regions and over complex terrain, such as the Adriatic region. We investigate the (potential) added value introduced by CPMs compared to classical “cumulus-parametrized” regional climate models (RCMs), reanalysis and station observations. For this purpose, wind components at 10 m level are used at 3-hourly frequency. All simulations cover a 10-year period, extending from 2000 to 2009. In terms of the standard statistical parameters such as correlation coefficient and temporal standard deviation, CPMs are very dependent on their parent RCM performance. However, the orographic forcing emphasizes the potential added value and CPMs contain some fine spatial scale variability (i.e., stronger extremes by 25% and more accurate wind direction) that is absent in coarser RCMs and reanalysis. The potential added value is higher in the cold season compared to the warm season due to the proportion of severe wind events. CPMs reproduce well the typical wind regimes along the Adriatic coast, namely Bora and Sirocco. The benefit of using CPMs is especially pronounced in simulating Bora maximum wind speeds in northern Adriatic and Sirocco frequencies in southern Adriatic. Based on our overall analysis, we conclude that CPMs provide added value compared to coarser models, especially in the complex coastal terrain.

Combined wind and wave resource assessment and energy extraction along the Indian coast

The present study analyses the combined offshore wind and wave resource potential along the Indian coast. The state-of-the-art ERA5 reanalysis datasets that provide wind fields at 100 m height have been used for the first time to assess wind resources along the Indian Coast. Further, wave parameters were generated using the WAVEWATCH III (WWIII) model. Long-term spatial air density was considered to find accurate wind power potential. The results reveal that the southern coast of India exhibits higher wind power density and moderate wave energy flux (up to 0.65 kW/m2 and 10 kW/m), respectively. This region has the lowest variability (coefficient of variation <1, skewness <1.5, and kurtosis <4) and less correlation (<0.4). A suitable hotspot is identified based on the collocation feasibility index and depth constraint after excluding conflicted regions. A comprehensive investigation of local wind and wave characteristics was performed at the hotspot. Further, the yearly and monthly cross-correlations between wind and wave at different time lags were analysed. Actual estimation of power generation is carried out with various combinations of wind turbine (SG8.0-167 DD) and wave energy converter (Oceantec). The outcome of the present study will help to initiate the development of joint offshore wind and wave energy farms in India.

Analytical Model for the Wind Farm Capacity Factor Based on Local Wind Characteristics

Analytical Model for the Wind Farm Capacity Factor Based on Local Wind Characteristics

Rapid shoreline flooding enhances water turbidity by sediment resuspension: An example in a large Tibetan lake

ABSTRACTRapid water level rise due to climate change has the potential to remobilize loose sediments along shorelines and increase the turbidity of nearshore waters, thereby impacting water quality and aquatic ecosystem health. Siling Lake is one of the largest and most rapidly expanding lakes on the Tibetan Plateau. Between 2000 and 2017, this lake experienced an increase in water level of about 8 m and a doubling in water turbidity. Here, using this lake as a study site, we used a wave model and high‐resolution remote sensing of turbidity (Landsat‐8) to assess the potential connection between water‐level rise, enhanced wind‐driven sediment resuspension and water turbidity. Our analysis revealed that strong bottom shear stresses triggered by wind‐generated waves over newly flooded areas were related to an increase in water turbidity. The spatial variability of Siling Lake turbidity showed a strong dependence on local wind characteristics and fetch. Two factors combined to drive the increase in turbidity: (1) high wave energy leading to high bottom shear stresses, and (2) flooding of unvegetated shallow areas. Using a new relationship between wave energy and turbidity developed here, we expect the increase in turbidity of Siling Lake to taper off in the near future due to the steep landscape surrounding the lake that will prevent further flooding. Our results imply that rising water levels along the coast are not only expected to influence terrestrial ecosystems but could also change water quality. The methodology presented herein could be applied to other shorelines affected by a rapid increase in water level. © 2020 John Wiley &amp; Sons, Ltd.

Does wind speed effects performance and cost of energy? A case study of wind farm

PurposeThe rapid rising of renewable energy sources particularly wind energy cannot be ignored. The numerical increase in wind energy farms throughout the world is the best example. The purpose of this paper is to assess the basic question of whether wind characteristics affect the performance and cost of energy. The importance of this question cannot be ruled out while comparing renewable energy to a conventional form of energy more specifically especially for the developing country where the cost of energy is very high.Design/methodology/approachThe research design of this paper is consists of an assessment of local wind characteristics of the wind farm site using Weibull k and c parameters. The performance model is used to assess the performance of the wind turbine (WT) corresponding to local wind characteristics. The wind correlation with WT in terms of changing wind speed has been assessed to quantify the effects of wind speed on the WT behavior and failure of WT components. Similarly, the power curve of WT is assessed and compared with the International Electrotechnical Commission standards 61400-12-2. The WT power coefficient and tip speed ratio corresponding to wind speed is also investigated. The energy volume and cost of energy lost model is used to determine the cost and volume loss of energy/kWh of the wind farm.FindingsThe findings of practical wind farms showed that the wind conditions of the site are showing a strong tendency that can be determined from the results of Weibull k and c parameters. The k and c parameters are observed to be 3.44 and 9.16 m/s, respectively, for a period of a year. The standard deviation is observed to be 2.56 for a period of a year. WT shows the efficient behavior can be obtained from the power coefficient and tip speed of WT at different wind speeds. Also, wind farm observation showed that to be some increasing wind speed cause of based WT component failures. The results of energy volume and cost/kWh assessment showed that the major portion of energy volume and cost of energy is lost owing to network, voltage dip and frequency surge, electrical and mechanical components failures.Originality/valueGenerally, it can be concluded that the WTs are now able to cope with variable wind speeds. However, the results of this paper are showing that WT performance and availability decreased due to increased wind speeds. It can also be a reason to decreased volume and increase the cost of energy/kWh.

Local wind characteristics on bridge deck of twin-box girder considering wind barriers by large-scale wind tunnel tests

Traffic accidents on bridges occur occasionally and have attracted the wide attention of the whole society as well as world. Therefore, researching and exploring the wind environment on bridge deck is a significant and urgent incident, which is able to provide crucial reference for vehicle driving safety. In this paper, the wind environments on the bridge deck of twin-box girder with large scale of 1:20.4 are investigated through wide-ranging wind tunnel tests. During the tests, multiple wind barriers with different heights, porosities and opening forms are considered precisely. Also, the wind environments of truss girder are studied and compared in the process of experiment. Eventually, after handling with the data, analyzing the figures and comparing with other test results, the most significant disciplines are as follows: The wind environments of twin-box girder and truss girder are fairly various; the power spectrum and the wind velocity of twin-box girder are much larger, and there is a lag at the wind velocity stabilization point of truss structure. At the same time, while the parameters of wind barriers change, lower porosity creates lower wind velocity and lower power spectrum. And the height of the wind barriers affects the wind profiles a lot on the windward lanes and lower power spectrum. In addition, the effects of the opening form on windproof and power spectrum are relatively limited.

A Study on the Wind Energy Potential in the Romanian Coastal Environment

At the European level, offshore wind projects are already considered a competitive market. Nevertheless, this is not yet the case of the enclosed sea basins, such as the Black Sea, where no offshore wind farm is operating at this moment. From this perspective, the objective of the present work is to identify the most suitable sites where a wind project can be developed in the Romanian coastal areas. Various parameters, such as wind speed, water depth, distance to shore, and turbine performance, are considered. A picture of the local wind characteristics is first provided considering 20 years of reanalysis data, which cover the time interval from January 1998 to December 2017. The results indicated that the best sites to implement a wind project are located in the northern sector of the Black Sea, close to the Danube Delta. It was also noticed an important variation of the wind speed between onshore and 20 km offshore, for which an increase of about 55% was estimated.

Selecting and testing of wind turbine blades of the local-wood growing fastly on local wind characteristics

The total potential of wind energy in Indonesia reaches 144 GW. This wind energy potential is dominated by small wind speeds ranging from 4-6 m / s and about 113 GW. This is the reason why the development of small-scale wind powerplant is more feasible to be developed in Indonesia. The characteristics of local wind and geographical conditions of Indonesia which is an archipelagic country are fundamental in designing wind power and utilizing of local materials. This study aims to get local fast-growing wood of wind turbines blades in Indonesia, which has the best physical and mechanical properties of wood, and is tested computationally on certain airfoils and shows a uniform distribution of stress. The types of wood are tested in this study were Sengon (Albizia chinensis), Jabon (Antocephalus cadamba), and Balsa (Ochroma Rowlee grandiflorum). The test covers the basic properties of the wood, physical and mechanical properties. The test results showed that Jabon have density 0.34 was the best compared to Sengon (0.24) and balsa (0.18). The best dimensional stability (T/R Ratios) are Jabon (1.97), sengon (2.19) and balsa (2.84), respectively. With the highest density result and the lowest dimensional stability value, mechanical testing of Jabon wood shows the best mechanical properties. The simulation result using Q-Blade software was obtained airfoil NACA 4415 most suitable for local wind characteristics, and got the low value of stress and distribution color uniformly on each wood.

Exoplanets as probes of the winds of host stars: the case of the M dwarf GJ 436

Winds of cool dwarfs are difficult to observe, with only a few M dwarfs presenting observationally-derived mass-loss rates (Mdot), which span several orders of magnitude. Close-in exoplanets are conveniently positioned in the inner regions of stellar winds and can, thus, be used to probe the otherwise-unobservable local properties of their host-stars' winds. Here, we use local stellar wind characteristics observationally-derived in the studies of atmospheric evaporation of the warm-neptune GJ436 b to derive the global characteristics of the wind of its M-dwarf host. Using an isothermal wind model, we constrain the stellar wind temperature to be in the range [0.36,0.43] MK, with Mdot=[0.5,2.5] x 10^{-15} Msyn/yr. By computing the pressure balance between the stellar wind and the interstellar medium, we derive the size of the astrophere of GJ436 to be around 25 au, significantly more compact than the heliosphere. We demonstrate in this paper that transmission spectroscopy, coupled to planetary atmospheric evaporation and stellar wind models, can be a useful tool for constraining the large-scale wind structure of planet-hosting stars. Extending our approach to future planetary systems discoveries will open new perspectives for the combined characterisation of planetary exospheres and winds of cool dwarf stars.

Wind tunnel study of wind structure at a mountainous bridge location

Wind tunnel tests of a 1/2200-scale mountainous terrain model have been carried out to investigate local wind characteristics at a bridge location in southeast Tibet, China. Flows at five key locations on the bridge at deck level were measured for 26 directions. It was observed that wind characteristics (including mean wind velocity and overall turbulence intensity) vary significantly depending on the approaching wind direction and measurement position. The wind inclination angle measured in the study fluctuated between $-18^{\circ}$ and $+16^{\circ}$ and the ratio of mean wind velocity to reference wind velocity was small when the wind inclination angles were large, especially for positive wind inclination angles. The design standard wind speed and the minimum critical wind speed for flutter rely on the wind inclination angle and should be determined from the results of such tests. The variation of wind speed with wind inclination angles should be of the asymmetry step type. The turbulence characteristics of the wind were found to be similar to real atmospheric flows.

Fatigue Life Assessment of Cracked High-Mast Illumination Poles

This paper presents the findings of a research program that was conducted to evaluate the probability of failure of high-mast illumination poles (HMIPs) with preexisting cracks at the pole-to-base plate connection detail. A simplified reliability-based analysis framework is presented to evaluate the safe service life of the cracked HMIPs. Vibrations induced by both vortex shedding and natural wind gusts are considered. The influence of different parameters is assessed, including pole geometry, pole location, terrain effects, local wind characteristics, and the assumed level of fatigue degradation attributable to the presence of a preexisting crack. The safe service lives of different standard HMIP designs that are commonly used by the Texas DOT are calculated. The results indicate that the degradation of the poles is predominantly attributable to vortex shedding–induced vibrations in the second and third vibration modes. The findings also demonstrate that the safe service life of a HMIP depends primarily on the effective stress range at the base of the pole attributable to wind-loading effects.

Wind distribution and capacity factor estimation for wind turbines in the coastal region of South Africa

The operating curve parameters of a wind turbine should match the local wind regime optimally to ensure maximum exploitation of available energy in a mass of moving air. This paper provides estimates of the capacity factor of 20 commercially available wind turbines, based on the local wind characteristics of ten different sites located in the Western Cape region of South Africa. Ten-min average time series wind-speed data for a period of 1 year are used for the study. First, the wind distribution that best models the local wind regime of the sites is determined. This is based on root mean square error (RMSE) and coefficient of determination (R2) which are used to test goodness of fit. First, annual, seasonal, diurnal and peak period-capacity factor are estimated analytically. Then, the influence of turbine power curve parameters on the capacity factor is investigated. Some of the key results show that the wind distribution of the entire site can best be modelled statistically using the Weibull distribution. Site WM05 (Napier) presents the highest capacity factor for all the turbines. This indicates that this site has the highest wind power potential of all the available sites. Site WM02 (Calvinia) has the lowest capacity factor i.e. lowest wind power potential. This paper can assist in the planning and development of large-scale wind power-generating sites in South Africa.

Local Wind Characteristics for East Thrace, Turkey

In this study, 8 stations located in east Thrace in the northwest of Turkey have been taken into consideration. The wind speed data and the present power potential analysis of these stations have been calculated and the wind characteristics of the territory have been determined. Edirne, Lüleburgaz, and Kirklareli stations have been determined as the stations that are inefficient of the wind speed. The maximum wind speed value gained at these stations at 60 m high has been determined as 5.48 ms−1 in 1979. The most efficient stations of wind speed potential have been determined as Çorlu and Malkara stations. It has been realized that maximum power up to 139.03 Wm−2 values would be gained from these stations. The highest wind speed value has been derived as 10.01 ms−1 at Çorlu in 1976. Also, it was discovered that the wind speed of four stations was reducing year after year and this decrement was statistically significant. The dispersals have been introduced showing the relationship between the area's wind speeds with the percent frequency value. And it has been stabilized that the wind is dominantly blowing through the ways between geographical north-east and west-south.

Modelling the outcrossing between genetically modified and conventional maize with equation discovery

Many studies explore the feasibility of co-existence between genetically modified (GM) and conventional (non-GM) crops. An important research topic in these studies is the process of outcrossing, i.e., the process of gene flow via pollen flow from GM to non-GM crops. In this paper, we address a new modelling approach to define the environmentally driven processes of outcrossing for maize from existing empirical datasets. In particular, we use equation discovery methodology that combines background knowledge and empirical data from several studies. We induce models that predict the degree of outcrossing rate between the donor (GM) and the recipient (non-GM) maize field from the distance between the fields and the local wind characteristics (speed, direction and duration). This results in highly accurate models, for which both variables (distance and wind) are essential and of roughly equal importance.

The role of non-prevailing wind direction on resuspension and redistribution of sediments in a shallow lake

Sediment resuspension can significantly affect the light climate and internal nutrient loading in shallow lakes. To predict wind-induced resuspension, a critical bottom shear stress or critical depth for the whole lake is typically used. It is suggested here that the availability of resuspendable material must also be considered and that this availability depends on local wind characteristics. The objective of this study was to show a connection between patterns of resuspension and accumulation of sediments and the prevailing wind directions. The near-shore sediments in the shallow Lake Krankesjon (surface area = 3 km2) in southern Sweden were characterized by a 5-graded resuspension potential scale and organic content. The spatial variability in sediment characteristics was compared to local wind statistics. This comparison showed that bottoms with low resuspension potential (sandy with low organic content) were located where waves from prevailing wind direction were acting, and bottoms with high resuspension potential (soft sediments with high organic content) were located to the lee-side of the prevailing wind directions. Intensive continuous turbidity measurements showed that winds above 10 m/s in directions other than the prevailing ones brought much material in suspension, while winds in the prevailing direction did not cause any increase in turbidity. The prevailing winds erode the bottom on one side of the lake, depositing resuspended material predominantly on the opposite side, where it can be resuspended by winds from non-revailing directions. Information about the local wind pattern can improve modeling and understanding of resuspension and redistribution of ediments in shallow lakes.