scholarly journals Estimation of the Tower Shape Effect on the Stress–Strain Behavior of Wind Turbines Operating under Offshore Boundary Conditions

Inventions ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 11
Author(s):  
Alexandra Ionelia Diaconita ◽  
Gabriel Andrei ◽  
Eugen Rusu
Keyword(s):  
Wind Turbine ◽  
Weather Conditions ◽  
Operating Conditions ◽  
The Black Sea ◽  
Shape Effect ◽  
Strain Behavior ◽  
Wind Speeds ◽  
Extreme Wind ◽  
Extreme Wind Speeds

The metal tower, or the pylon, is one of the most important elements in the construction of a wind turbine. It has the role of supporting the entire wind turbine, and it also allows access for inspection and conducting planned maintenance and repairs. Moreover, the tower ensures support for the structure and strengthens the whole assembly. It has a particularly important role, as it has to face very severe weather conditions. The present study aims to analyze the forces and moments resulting from the action of the wind on the tower of a wind turbine. Two important load cases are considered, namely, the load under operating conditions and the ultimate load under 50 year wind conditions. For this purpose, cylindrical and conical geometric shapes of the tower were chosen. These were analyzed under the action of both normal and extreme wind speeds. Then, the behavior of the two towers under the action of the wind speed for a location in the Black Sea was analyzed. Finally, in an attempt to make the structure more economical, the thickness of the shell was reduced.

scholarly journals Separated Pitch Control at Tip: Innovative Blade Design Explorations for Large MW Wind Turbine Blades

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Ranjeet Agarwala ◽  
Paul I. Ro
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Pitch Control ◽  
Wind Speeds ◽  
Extreme Wind ◽  
Blade Tip ◽  
Low Wind Speeds ◽  
Extreme Wind Speeds

This paper focuses on the deployment and evaluation of a separated pitch control at blade tip (SePCaT) control strategy for large megawatt (MW) wind turbine blade and explorations of innovative blade designs as a result of such deployment. SePCaT configurations varied from five to thirty percent of the blade length in 5 percentage increments (SePCaT5, SePCaT10, SePCaT15, SePCaT20, SePCaT25, and SePCaT30) are evaluated by comparing them to aerodynamical responses of the traditional blade. For low, moderate, high, and extreme wind speed variations treated as 10, 20, 30, and 40 percent of reference wind speeds, rotor power abatement in region 3 of the wind speed power curve is realized by feathering full length blade by 6, 9, 12, and 14 degrees, respectively. Feathering SePCaT30, SePCaT25, SePCaT20, and SePCaT15 by 14, 16, 26, and 30 degrees, respectively, achieves the same power abatement results when compared to traditional blade at low wind speeds. Feathering SePCaT30, SePCaT25, and SePCaT20 by 18, 26, and 30 degrees on the other hand has the same effect at high wind speeds. SePCaT30 feathered to 26 and 30 degrees has the same abatement effects when compared to traditional blade at high and extreme wind speeds.

Forecasting of Tornadoes and Downbursts

2020 ◽  
Author(s):  
Djordje Romanic
Keyword(s):  
Chaos Theory ◽  
Prediction Models ◽  
Weather Prediction ◽  
Small Scale ◽  
Weather Forecasts ◽  
Wind Speeds ◽  
The Past ◽  
Extreme Wind ◽  
Extreme Wind Speeds ◽  
Numerical Weather Prediction Models

Tornadoes and downbursts cause extreme wind speeds that often present a threat to human safety, structures, and the environment. While the accuracy of weather forecasts has increased manifold over the past several decades, the current numerical weather prediction models are still not capable of explicitly resolving tornadoes and small-scale downbursts in their operational applications. This chapter describes some of the physical (e.g., tornadogenesis and downburst formation), mathematical (e.g., chaos theory), and computational (e.g., grid resolution) challenges that meteorologists currently face in tornado and downburst forecasting.

Midlatitude cyclones in convection permitting climate simulations: the added value offered for extreme wind speeds and sting-jets

2021 ◽  
Author(s):  
Colin Manning ◽  
Elizabeth Kendon ◽  
Hayley Fowler ◽  
Nigel Roberts ◽  
Segolene Berthou ◽  
...  
Keyword(s):  
Climate Model ◽  
Surface Wind ◽  
Added Value ◽  
Large Contribution ◽  
High Wind ◽  
Wind Speeds ◽  
Wind Gusts ◽  
Climate Simulations ◽  
Extreme Wind ◽  
Extreme Wind Speeds

<p>Extra-tropical windstorms are one of the costliest natural hazards affecting Europe, and windstorms that develop a phenomenon known as a sting-jet account for some of the most damaging storms. A sting-jet (SJ) is a mesoscale core of high wind speeds that occurs in particular types of cyclones, specifically Shapiro-Keyser (SK) cyclones, and can produce extremely damaging surface wind gusts. High-resolution climate models are required to adequately model SJs and so it is difficult to gauge their contribution to current and future wind risk. In this study, we develop a low-cost methodology to automate the detection of sting jets, using the characteristic warm seclusion of SK cyclones and the slantwise descent of high wind speeds, within pan-European 2.2km convection-permitting climate model (CPM) simulations. Following this, we quantify the contribution of such storms to wind risk in Northern Europe in current and future climate simulations, and secondly assess the added value offered by the CPM compared to a traditional coarse-resolution climate model. This presentation will give an overview of the developed methods and the results of our analysis.</p><p>Comparing with observations, we find that the representation of wind gusts is improved in the CPM compared to ERA-Interim reanalysis data. Storm severity metrics indicate that SK cyclones account for the majority of the most damaging windstorms. The future simulation produces a large increase (>100%) in the number of storms exceeding high thresholds of the storm metric, with a large contribution to this change (40%) coming from windstorms in which a sting-jet is detected. Finally, we see a systematic underestimation in the GCM compared to the CPM in the frequency of extreme wind speeds at 850hPa in the cold sector of cyclones, likely related to better representation of sting-jets and the cold conveyor belt in the CPM. This underestimation is between 20-40% and increases with increasing wind speed above 35m/s. We conclude that the CPM adds value in the representation of severe surface wind gusts, providing more reliable future projections and improved input for impact models.</p>

Changes in extreme wind speeds in NW Europe simulated by generalized linear models

2005 ◽  
Vol 83 (1-4) ◽  
pp. 121-137 ◽  
Author(s):  
Z. Yan ◽  
S. Bate ◽  
R. E. Chandler ◽  
V. Isham ◽  
H. Wheater
Keyword(s):  
Generalized Linear Models ◽  
Linear Models ◽  
Wind Speeds ◽  
Extreme Wind ◽  
Extreme Wind Speeds ◽  
Nw Europe

scholarly journals Test campaign of a ducted wind turbine in real operating conditions

2019 ◽  
Vol 113 ◽  
pp. 03005
Author(s):  
Enrico Valditerra ◽  
Massimo Rivarolo ◽  
Aristide F. Massardo ◽  
Marco Gualco
Keyword(s):  
Wind Turbine ◽  
Urban Areas ◽  
Energy Production ◽  
Electrical Energy ◽  
Clean Energy ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Ambient Conditions ◽  
Wind Speeds ◽  
Electrical Energy Production

Wind turbine installation worldwide has increased at unrested pace, as it represents a 100% clean energy with zero CO2 and pollutant emissions. However, visual and acoustic impact of wind turbines is still a drawback, in particular in urban areas. This paper focuses on the performance evaluation of an innovative horizontal axis ducted wind turbine, installed in the harbour of Genova (Italy) in 2018: the turbine was designed in order to minimize visual and acoustic impacts and maximize electrical energy production, also during low wind speed periods. The preliminary study and experimental analyses, performed by the authors in a previous study, showed promising results in terms of energy production, compared to a traditional generator ( factor >2.5 on power output). In the present paper, the test campaign on a scaled-up prototype, installed in the urban area of Genova, is performed, with a twofold objective: (i) comparison of the ducted innovative turbine with a standard one, in order to verify the increase in energy production; (ii) analysis of the innovative turbine for different wind speeds and directions, evaluating the influence of ambient conditions on performance. Finally, based on the obtained results, an improved setup is proposed for the ducted wind turbine, in order to further increase energy production mitigating its visual impact.

scholarly journals At What Time of Day Do Daily Extreme Near-Surface Wind Speeds Occur?

2014 ◽  
Vol 27 (11) ◽  
pp. 4226-4244 ◽  
Author(s):  
Robert Fajber ◽  
Adam H. Monahan ◽  
William J. Merryfield
Keyword(s):  
Extreme Values ◽  
Mechanistic Model ◽  
Surface Wind ◽  
Time Of Day ◽  
Near Surface ◽  
Wind Speeds ◽  
Boundary Layer Processes ◽  
Early Afternoon ◽  
Extreme Wind ◽  
Extreme Wind Speeds

Abstract The timing of daily extreme wind speeds from 10 to 200 m is considered using 11 yr of 10-min averaged data from the 213-m tower at Cabauw, the Netherlands. This analysis is complicated by the tendency of autocorrelated time series to take their extreme values near the beginning or end of a fixed window in time, even when the series is stationary. It is demonstrated that a simple averaging procedure using different base times to define the day effectively suppresses this “edge effect” and enhances the intrinsic nonstationarity associated with diurnal variations in boundary layer processes. It is found that daily extreme wind speeds at 10 m are most likely in the early afternoon, whereas those at 200 m are most likely in between midnight and sunrise. An analysis of the joint distribution of the timing of extremes at these two altitudes indicates the presence of two regimes: one in which the timing is synchronized between these two layers, and the other in which the occurrence of extremes is asynchronous. These results are interpreted physically using an idealized mechanistic model of the surface layer momentum budget.

scholarly journals Analysis of the Patent of a Protective Cover for Vertical-Axis Wind Turbines (VAWTs): Simulations of Wind Flow

2020 ◽  
Vol 12 (18) ◽  
pp. 7818
Author(s):  
Jose Alberto Moleón Baca ◽  
Antonio Jesús Expósito González ◽  
Candido Gutiérrez Montes
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
High Speed ◽  
Experimental Tests ◽  
Weather Conditions ◽  
Vertical Axis ◽  
Good Alternative ◽  
Wind Speeds ◽  
Vertical Axis Wind Turbines

This paper presents a numerical and experimental analysis of the patent of a device to be used in vertical-axis wind turbines (VAWTs) under extreme wind conditions. The device consists of two hemispheres interconnected by a set of conveniently implemented variable section ducts through which the wind circulates to the blades. Furthermore, the design of the cross-section of the ducts allows the control of the wind speed inside the device. These ducts are intended to work as diffusers or nozzles, depending on the needs of the installation site. Simulations were performed for the case of high-speed external wind, for which the ducts act as diffusers to reduce wind speed and maintain a well-functioning internal turbine. Four different patent designs were analyzed, focusing on turbine performance and generated power. The results indicate that the patent allows the generation of electric power for a greater range of wind speeds than with a normal wind turbine. The results support that this patent may be a good alternative for wind power generation in geographic areas with extreme weather conditions or with maintained or strong gusty wind. Experimental tests were carried out on the movement of the blades using the available model. Finally, the power curve of the model of this wind turbine was obtained.

scholarly journals Study on the Influence of Baseline Control System on the Fragility of Large-Scale Wind Turbine considering Seismic-Aerodynamic Combination

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chenyang Yuan ◽  
Jing Li ◽  
Jianyun Chen ◽  
Qiang Xu ◽  
Yunfei Xie
Keyword(s):  
Control System ◽  
Wind Speed ◽  
Wind Turbine ◽  
Large Scale ◽  
Fragility Curves ◽  
Operating Conditions ◽  
Ground Acceleration ◽  
Wind Speeds ◽  
Speed Range ◽  
Wind Actions

The purpose of this paper is to explore the effect of the baseline control system (BCS) on the fragility of large-scale wind turbine when seismic and wind actions are considered simultaneously. The BCS is used to control the power output by regulating rotor speed and blade-pitch angle in real time. In this study, the fragility analysis was performed and compared between two models using different peak ground acceleration, wind speeds, and specified critical levels. The fragility curves with different wind conditions are obtained using the multiple stripe analysis (MSA) method. The calculation results show that the probability of exceedance specified critical level increases as the wind speed increases in model 1 without considering BCS, while does not have an obvious change in the below-rated wind speed range and has a significant decrease in the above-rated wind speed range in model 2 with considering BCS. The comparison depicts that if the BCS is neglected, the fragility of large-scale wind turbine will be underestimated in around the cut-in wind speed range and overestimated in the over-rated wind speed range. It is concluded that the BCS has a great effect on the fragility especially within the operating conditions when the rated wind speed is exceeded, and it should be considered when estimating the fragility of wind turbine subjected to the interaction of seismic and aerodynamic loads.

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