scholarly journals The Yawing Behavior of Horizontal-Axis Wind Turbines: A Numerical and Experimental Analysis

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 15 ◽  
Author(s):  
Francesco Castellani ◽  
Davide Astolfi ◽  
Francesco Natili ◽  
Francesco Mari

The yawing of horizontal-axis wind turbines (HAWT) is a major topic in the comprehension of the dynamical behavior of these kinds of devices. It is important for the study of mechanical loads to which wind turbines are subjected and it is important for the optimization of wind farms because the yaw active control can steer the wakes between nearby wind turbines. On these grounds, this work is devoted to the numerical and experimental analysis of the yawing behavior of a HAWT. The experimental tests have been performed at the wind tunnel of the University of Perugia on a three-bladed small HAWT prototype, having two meters of rotor diameter. Two numerical set ups have been selected: a proprietary code based on the Blade Element Momentum theory (BEM) and the aeroelastic simulation software FAST, developed at the National Renewable Energy Laboratory (NREL) in Golden, CO, USA. The behavior of the test wind turbine up to ± 45 ∘ of yaw offset is studied. The performances (power coefficient C P ) and the mechanical behavior (thrust coefficient C T ) are studied and the predictions of the numerical models are compared against the wind tunnel measurements. The results for C T inspire a subsequent study: its behavior as a function of the azimuth angle is studied and the periodic component equal to the blade passing frequency 3P is observed. The fluctuation intensity decreases with the yaw angle because the distance between tower and blade increases. Consequently, the tower interference is studied through the comparison of measurements and simulations as regards the fore-aft vibration spectrum and the force on top of the tower.

2022 ◽  
pp. 1-34
Author(s):  
Ojing Siram ◽  
Neha Kesharwani ◽  
Niranjan Sahoo ◽  
Ujjwal K. Saha

Abstract In recent times, the application of small-scale horizontal axis wind turbines (SHAWTs) has drawn interest in certain areas where the energy demand is minimal. These turbines, operating mostly at low Reynolds number (Re) and low tip speed ratio (λ) applications, can be used as stand-alone systems. The present study aims at the design, development, and testing of a series of SHAWT models. On the basis of aerodynamic characteristics, four SHAWT models viz., M1, M2, M3, and M4 composed of E216, SG6043, NACA63415, and NACA0012 airfoils, respectively have been developed. Initially, the rotors are designed through blade element momentum theory (BEMT), and their power coefficient have been evaluated. Thence, the developed rotors are tested in a low-speed wind tunnel to find their rotational frequency, power and power coefficient at design and off-design conditions. From BEMT analysis, M1 shows a maximum power coefficient (Cpmax) of 0.37 at λ = 2.5. The subsequent wind tunnel tests on M1, M2, M3, and M4 at 9 m/s show the Cpmax values to be 0.34, 0.30, 0.28, and 0.156, respectively. Thus, from the experiments, the M1 rotor is found to be favourable than the other three rotors, and its Cpmax value is found to be about 92% of BEMT prediction. Further, the effect of pitch angle (θp) on Cp of the model rotors is also examined, where M1 is found to produce a satisfactory performance within ±5° from the design pitch angle (θp, design).


2018 ◽  
Vol 43 (3) ◽  
pp. 247-262 ◽  
Author(s):  
Palanisamy Mohan Kumar ◽  
M Mohan Ram Surya ◽  
Srikanth Narasimalu ◽  
Teik-Cheng Lim

Savonius wind turbines have distinct advantages in terms of simplicity, low noise, and ease of manufacturing, yet they are not preferred for large-scale power generation due to their lower aerodynamic performance and high wind loads. This study is aimed at reducing the thrust load with retractable type telescopic blades. This novel telescopic Savonius turbine is tested in an open jet wind tunnel to assess the performance in terms of torque, power, and thrust on the rotor. The dynamic and static characteristics are obtained for both extended and retracted configuration after correcting the experimental data for wind tunnel blockage. A preliminary numerical study is carried out in an effort to determine the variation of the drag coefficient in relation to the bucket thickness. The proposed telescopic turbine demonstrates a reduction in thrust load of 72.4% with a maximum power coefficient of 0.14 at the tip speed ratio of 0.7 compared to an extended operating configuration, similar to a conventional Savonius turbine. Thus, the telescopic Savonius turbine can be scaled up to higher kilowatt capacity with the cost comparable to other high-speed rotors such as Darrieus or horizontal axis wind turbines.


2011 ◽  
Vol 382 ◽  
pp. 129-132
Author(s):  
Xu Ning Mao ◽  
Ji Shun Li ◽  
Yi Liu

In this study, the dynamic characteristics of three-blade horizontal¬-axis wind turbines were simulated, based on the aerodynamic software AeroDyn, wind turbine design software FAST and mechanical dynamics simulation software ADAMS. AeroDyn and FAST are Interface codes for ADAMS. As the pre-processor of ADAMS, FAST code helps to build wind turbine model as well as constrains ,while AeroDyn code applies wind field data to the model. At last the model was imported into ADAMS to be simulated. In this way, the dynamic operating characteristics of three-blade horizontal¬-axis wind turbines can be obtained. And the load-time curves of the blade roots can also be gotten. Results show that the method adopted is feasible and reliable.


2017 ◽  
Vol 6 (2) ◽  
pp. 119
Author(s):  
Le Quang Sang ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
Qing'an Li

Offshore wind is generally stronger and more consistent than wind on land. A large part of the offshore wind resource is however located in deep water, where floating wind turbines can harvest more energy. This paper describes a systematic experiment and a simulation analysis (FAST code) about the cyclic pitch control of blades. This work was performed to investigate performance fluctuation of a floating wind turbine utilizing cyclic pitch control. The experiment was carried out in an open wind tunnel with mainstream wind velocity of 10 m/s with the front inflow wind and the oblique inflow wind conditions. A model wind turbine is two-bladed downwind wind turbine with diameter of 1.6 m. Moment and force acts on the model wind turbine are measured by a six-component balance. Fluctuation of power coefficient and thrust coefficient is investigated in the cyclic pitch control. The model wind turbine and the experimental conditions were simulated by FAST code. The comparison of the experimental data and the simulation results of FAST code show that the power coefficient and thrust coefficient are in good agreement. Keywords: Floating Offshore Wind Turbine, Aerodynamic Forces, Cyclic Pitch Control, FAST Code, Wind Tunnel ExperimentArticle History: Received February 11th 2017; Received in revised form April 29th 2017; Accepted June 2nd 2017; Available onlineHow to Cite This Article: Sang, L.Q., Maeda, T., Kamada, Y., and Li, Q. (2017) Experiment and simulation effect of cyclic pitch control on performance of horizontal axis wind turbine to International Journal of Renewable Energy Develeopment, 6(2), 119-125.https://doi.org/10.14710/ijred.6.2.119-125


2004 ◽  
Vol 28 (2) ◽  
pp. 197-212 ◽  
Author(s):  
Takao Maeda ◽  
Takeshi Yokota ◽  
Yukimaru Shimizu ◽  
Kazuhiro Adachi

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