scholarly journals Dynamic Amplification of Gust-Induced Aerodynamic Loads Acting on a Wind Turbine during Typhoons in Taiwan

2021 ◽  
Vol 9 (4) ◽  
pp. 352
Author(s):  
Tsung-Yueh Lin ◽  
Chun-Yu Yang ◽  
Shiu-Wu Chau ◽  
Jen-Shiang Kouh
Keyword(s):  
Wind Turbine ◽  
Numerical Approach ◽  
International Electrotechnical Commission ◽  
Onshore Wind ◽  
Aerodynamic Loads ◽  
Extreme Wind ◽  
Proper Definition ◽  
Extreme Wind Speed ◽  
Dynamic Amplification ◽  
Definition Of

Typhoons, such as Soudelor, which caused the collapse of several onshore wind turbines in 2015, pose a considerable challenge to Taiwan’s wind energy industry. In this study the characteristics of the aerodynamic loads acting on a wind turbine due to wind gusts in a typhoon are studied with a view to providing a proper definition of the S-Class wind turbine proposed in International Electrotechnical Commission (IEC) 61400-1. Furthermore, based on analysis of wind data during typhoons, as obtained from the meteorological mast in the Zhangbin coastal area, an extreme wind speed and gust model corresponding to the typhoon wind conditions in Taiwan are herein proposed. Finally, the flow fields around a parked wind turbine experiencing both an unsteady gust and a steady extreme wind were simulated by a numerical approach. Numerical results show that the aerodynamic shear force and overturning moment acting on the target wind turbine in a steady wind are significantly lower than those under an unsteady gust. The gust-induced amplification factors for aerodynamic loadings are then deduced from numerical simulations of extreme wind conditions.

scholarly journals The selection of directional sectors for the analysis of extreme wind speed

2019 ◽  
Vol 19 (1) ◽  
pp. 221-236 ◽  
Author(s):  
Pedro Folgueras ◽  
Sebastián Solari ◽  
Miguel Ángel Losada
Keyword(s):  
Wind Speed ◽  
Rational Method ◽  
Sources Of Uncertainty ◽  
La Plata ◽  
Extreme Wind ◽  
Design Wind Speed ◽  
Extreme Wind Speed ◽  
Definition Of ◽  
Objective Tool ◽  
Selection Of

Abstract. This paper presents a rational method for the selection of the most suitable directional sectors in the analysis of extreme wind loads on structures. It takes into consideration the main sources of uncertainty stemming from sector selection and leads to the definition of independent and statistically homogeneous directional sectors. This method is applied to the selection of directional sectors for the calculation of the design wind speed of a structure located at the mouth of the Río de la Plata. The results in the estimated reliability and costs were compared to those obtained with conventional engineering methods, revealing significant differences. It was found that the proposed method is a simple and objective tool for the selection of directional sectors, which comply with the working hypothesis of the directional models, and offers better guarantees for dimensioning than the use of more traditional engineering approaches for sectorial division.

scholarly journals The selection of directional sectors for the analysis of extreme wind speed

2018 ◽  
Author(s):  
Pedro Folgueras ◽  
Sebastián Solari ◽  
Miguel Ángel Losada
Keyword(s):  
Wind Speed ◽  
Rational Method ◽  
Sources Of Uncertainty ◽  
La Plata ◽  
Extreme Wind ◽  
Design Wind Speed ◽  
Extreme Wind Speed ◽  
Definition Of ◽  
Objective Tool ◽  
Selection Of

Abstract. This paper presents a rational method for the selection of the most suitable directional sectors in the analysis of extreme wind loads on structures. It takes into consideration the main sources of uncertainty stemming from sector selection, and leads to the definition of independent and statistically homogeneous directional sectors. This method is applied to the selection of directional sectors for the calculation of the design wind speed of a structure located at the mouth of the Río de la Plata. The results in the estimated reliability and costs were compared to those obtained with conventional engineering methods revealing significant differences. It was found that the proposed method is a simple and objective tool for the selection of directional sectors, which comply with the working hypothesis of the directional models and offers better guarantees for dimensioning than the use of more traditional engineering approaches for sectorial division.

scholarly journals Study effect of extreme wind direction change on 3-bladed horizontal axis wind turbine

2019 ◽  
Vol 8 (3) ◽  
pp. 261-266
Author(s):  
Le Quang Sang ◽  
Takao Maeda ◽  
Yasunari Kamada
Keyword(s):  
Wind Turbine ◽  
Wind Direction ◽  
Horizontal Axis ◽  
International Electrotechnical Commission ◽  
Wind Condition ◽  
Wind Regime ◽  
Horizontal Axis Wind Turbine ◽  
Direction Change ◽  
Extreme Wind ◽  
Pitch Moment

The Horizontal Axis Wind Turbines (HAWT) are used very popular in the world. They were installed mainly on land. However, on the land, the wind regime change is very complex such as high turbulence and constantly changing wind direction. In the International Electrotechnical Commission (IEC) 61400-1 standard, the wind regime is devided into the normal wind conditions and the extreme wind conditions. This study will focus on the extreme wind direction change and estimate the aerodynamic forces acting on a 3-bladed HAWT under this condition. Because the extreme wind direction change may cause extreme loads and it will affect the lifetime of HAWTs. This issue is experimented in the wind tunnel in Mie University, Japan to understand these effects. The wind turbine model is the 3-bladed HAWT type and using Avistar airfoil for making blades. A 6-component balance is used to measure the forces and the moments acting on the entire wind turbine in the three directions of x, y and z-axes. This study estimates the load fluctuation of the 3-bladed wind turbine under extreme wind direction change. The results show that the yaw moment and the pitch moment under the extreme wind direction change fluctuate larger than the normal wind condition. Specifically, before the sudden wind direction change happened, the averaged maximum pitch moment MX is -1.78 Nm, and after that MX is 4.45 Nm at inrush azimuth of 0°.©2019. CBIORE-IJRED. All rights reserved

scholarly journals Performance and FMECA of a wind turbine based on SCADA and lidar data

2019 ◽  
Vol 8 (2) ◽  
pp. 101
Author(s):  
A. Bennouk ◽  
A. Nejmi ◽  
M. Ramzi
Keyword(s):  
Wind Turbine ◽  
Energy Gap ◽  
Performance Study ◽  
Onshore Wind ◽  
Mode Effects ◽  
Turbine Performance ◽  
Definition Of ◽  
Criticality Analysis ◽  
Performance Calculation

<p>This paper presents an approach to identify risks for different failures that could affect wind turbine performance, and reduce the measured annual electrical production (MAEP). The proposed approach is based on FMECA (failure mode, effects and criticality analysis) and wind turbine performance study. We present firstly the methodology of performance calculation based on IEC 61400 standard, then we identify the energy gap between the MAEP and WAEP for the case study, we present an extended and reviewed FMECA, by introducing definition of factors related to environment, health and security. As a result we present an actions plan for similar failures deduced from wind performance study and risk-based FMECA, in order to reduce failure risks and optimize production by consequence. The case study is a 2.3 MW onshore wind turbine, different data that are used in this paper were collected from SCADA and lidar.</p>

IEA Wind TCP Task 37: Definition of the IEA 15-Megawatt Offshore Reference Wind Turbine

2020 ◽  
Author(s):  
Evan Gaertner ◽  
Jennifer Rinker ◽  
Latha Sethuraman ◽  
Frederik Zahle ◽  
Benjamin Anderson ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Definition Of

Simultaneous heat and mass transfer during evaporation from a film of liquid into the turbulent gas

1982 ◽  
Vol 47 (3) ◽  
pp. 766-775 ◽  
Author(s):  
Václav Kolář ◽  
Jan Červenka
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Driving Forces ◽  
Proper Definition ◽  
Definition Of ◽  
Simultaneous Heat ◽  
Theory And Experiment

The paper presents results obtained by processing a series of published experimental data on heat and mass transfer during evaporation of pure liquids from the free board of a liquid film into the turbulent gas phone. The data has been processed on the basis of the earlier theory of mechanism of heat and mass transfer. In spite of the fact that this process exhibits a strong Stefan's flow, the results indicate that with a proper definition of the driving forces the agreement between theory and experiment is very good.

scholarly journals A theoretical and numerical approach for selecting miniaturized antenna topologies on magneto-dielectric substrates

2015 ◽  
Vol 7 (3-4) ◽  
pp. 369-377 ◽  
Author(s):  
Alex Pacini ◽  
Alessandra Costanzo ◽  
Diego Masotti
Keyword(s):  
Near Field ◽  
Dielectric Materials ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Microwave Range ◽  
Dielectric Substrates ◽  
Full Wave ◽  
Miniaturized Antenna ◽  
Wavelength Radiation ◽  
Definition Of

An increasing interest is arising in developing miniaturized antennas in the microwave range. However, even when the adopted antennas dimensions are small compared with the wavelength, radiation performances have to be preserved to keep the system-operating conditions. For this purpose, magneto-dielectric materials are currently exploited as promising substrates, which allows us to reduce antenna dimensions by exploiting both relative permittivity and permeability. In this paper, we address generic antennas in resonant conditions and we develop a general theoretical approach, not based on simplified equivalent models, to establish topologies most suitable for exploiting high permeability and/or high-permittivity substrates, for miniaturization purposes. A novel definition of the region pertaining to the antenna near-field and of the associated field strength is proposed. It is then showed that radiation efficiency and bandwidth can be preserved only by a selected combinations of antenna topologies and substrate characteristics. Indeed, by the proposed independent approach, we confirm that non-dispersive magneto-dielectric materials with relative permeability greater than unit, can be efficiently adopted only by antennas that are mainly represented by equivalent magnetic sources. Conversely, if equivalent electric sources are involved, the antenna performances are significantly degraded. The theoretical results are validated by full-wave numerical simulations of reference topologies.

WoCoVA consensus on the clinical use of in-line filtration during intravenous infusions: Current evidence and recommendations for future research

2021 ◽  
pp. 112972982198916
Author(s):  
Ton Van Boxtel ◽  
Mauro Pittiruti ◽  
Annemarie Arkema ◽  
Patrick Ball ◽  
Giovanni Barone ◽  
...  
Keyword(s):  
Potential Benefit ◽  
Scientific Evidence ◽  
Venous Access ◽  
Current Evidence ◽  
Future Research ◽  
Global Awareness ◽  
Current State ◽  
Intravenous Infusions ◽  
Proper Definition ◽  
Definition Of

The need for filtering intravenous infusions has long been recognized in the field of venous access, though hard scientific evidence about the actual indications for in-line filters has been scarce. In the last few years, several papers and a few clinical studies have raised again this issue, suggesting that the time has come for a proper definition of the type of filtration, of its potential benefit, and of its proper indications in clinical practice. The WoCoVA Foundation, whose goal is to increase the global awareness on the risk of intravenous access and on patients’ safety, developed the project of a consensus on intravenous filtration. A panel of experts in different aspects of intravenous infusion was chosen to express the current state of knowledge about filtration and to indicate the direction of future research in this field. The present document reports the final conclusions of the panel.

Development and Field Testing of an Inclined Flanged Compact Diffuser for a Micro Wind Turbine

2014 ◽  
Author(s):  
Sandip Kale ◽  
S. N. Sapali
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Wind Turbines ◽  
Energy Production ◽  
Cost Effective ◽  
Field Testing ◽  
International Electrotechnical Commission ◽  
Average Wind Speed ◽  
Average Wind ◽  
Power Curves

Micro wind turbines installed in various applications, experience average wind speed for most of the time during operations. Power produced by the wind turbine is proportional to the cubic power of the wind velocity and a small increase in wind velocity results increases power output significantly. The approach wind velocity can be increased by covering traditional wind turbine with a diffuser. Researchers are continuously working to develop a compact, lightweight, cost effective and feasible diffuser for wind turbines. The present work carried out to develop a diffuser with these stated objectives. A compact, lightweight inclined flanged diffuser developed for a micro wind turbine. Bare micro wind turbine and wind turbine covered with developed efficient inclined flanged diffuser tested in the field as per International Electrotechnical Commission (IEC) standards and results presented in the form of power curves. The prediction of annual energy production for both wind turbines determined as per IEC standards.

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