Numerical simulation and model prediction of complex wind-turbine wakes

Author(s):  
Yi-Lei Song ◽  
Lin-Lin Tian ◽  
Ning Zhao
Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 776
Author(s):  
Byunghui Kim ◽  
Sang-June Park ◽  
Seokyoung Ahn ◽  
Myung-Gon Kim ◽  
Hyung-Gun Yang ◽  
...  

Although mega-watt class onshore and offshore wind power systems are used to generate power due to their cost-effectiveness, small wind power systems are important for household usages. Researchers have focused on aerodynamic characteristics as a conceptual design from their previous studies on Archimedes spiral wind turbines. Here, we verified the design of a small wind turbine AWM-750D (100 W capacity) via both numerical simulation and experimentation. We used commercial code ANSYS CFX for numerical simulation and compared turbulence models and surface roughness for determining the performance. To obtain reliable and robust blades, we analyzed the effective manufacturing method with Moldflow. Through a test with an open-suction type atmospheric boundary layer wind tunnel, we varied wind speed from 4.0 m/s to the rated value of 12.5 m/s and obtained 106 W, equivalent to a power coefficient of 0.205. In addition, we compared the numerical and experimental power vs. rotational speed and found the former is 6.5% lower than the latter. In this study, we proved that numerical simulations can act as design verification methods to predict wind turbine performances and reliable manufacturing. Through our research, we provided the prototype of a small wind turbine with 100 W to act as an efficient electric power supplier for households and also the stable manufacturing process for complex spiral blades using injection molding.


2017 ◽  
Vol 79 (7-3) ◽  
Author(s):  
Iham F. Zidane ◽  
Khalid M. Saqr ◽  
Greg Swadener ◽  
Xianghong Ma ◽  
Mohamed F. Shehadeh

Gulf and South African countries have enormous potential for wind energy. However, the emergence of sand storms in this region postulates performance and reliability challenges on wind turbines. This study investigates the effects of debris flow on wind turbine blade performance. In this paper, two-dimensional incompressible Navier-Stokes equations and the transition SST turbulence model are used to analyze the aerodynamic performance of NACA 63415 airfoil under clean and sandy conditions. The numerical simulation of the airfoil under clean surface condition is performed at Reynolds number 460×103, and the numerical results have a good consistency with the experimental data. The Discrete Phase Model has been used to investigate the role sand particles play in the aerodynamic performance degradation. The pressure and lift coefficients of the airfoil have been computed under different sand particles flow rates. The performance of the airfoil under different angle of attacks has been studied. Results showed that the blade lift coefficient can deteriorate by 28% in conditions relevant to the Gulf and South African countries sand storms. As a result, the numerical simulation method has been verified to be economically available for accurate estimation of the sand particles effect on the wind turbine blades.


Author(s):  
Tomoaki Utsunomiya ◽  
Shigeo Yoshida ◽  
Soichiro Kiyoki ◽  
Iku Sato ◽  
Shigesuke Ishida

In this paper, dynamic response of a Floating Offshore Wind Turbine (FOWT) with spar-type floating foundation at power generation is presented. The FOWT mounts a 100kW wind turbine of down-wind type, with the rotor’s diameter of 22m and a hub-height of 23.3m. The floating foundation consists of PC-steel hybrid spar. The upper part is made of steel whereas the lower part made of prestressed concrete segments. The FOWT was installed at the site about 1km offshore from Kabashima Island, Goto city, Nagasaki prefecture on June 11th, 2012. Since then, the field measurement had been made until its removal in June 2013. In this paper, the dynamic behavior during the power generation is presented, where the comparison with the numerical simulation by aero-hydro-servo-mooring dynamics coupled program is made.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6167
Author(s):  
Fang Feng ◽  
Guoqiang Tong ◽  
Yunfei Ma ◽  
Yan Li

In order to get rid of the impact of the global financial crisis and actively respond to global climate change, it has become a common choice for global economic development to develop clean energy such as wind energy, improve energy efficiency and reduce greenhouse gas emissions. With the advantages of simple structure, unnecessary facing the wind direction, and unique appearance, the vertical axis wind turbine (VAWT) attracts extensive attention in the field of small and medium wind turbines. The lift-type VAWT exhibits outstanding aerodynamic characteristics at a high tip speed ratio, while the starting characteristics are generally undesirable at a low wind speed; thus, how to improve the starting characteristics of the lift-type VAWT has always been an important issue. In this paper, a lift-drag combined starter (LDCS) suitable for lift-type VAWT was proposed to optimize the starting characteristics of lift-type VAWT. With semi-elliptical drag blades and lift blades equipped on the middle and rear part outside the starter, the structure is characterized by lift-drag combination, weakening the adverse effect of the starter with semi-elliptical drag blades alone on the output performance of the original lift-type VAWT and improving the characteristics of the lift-drag combined VAWT. The static characteristic is one of the important starting characteristics of the wind turbine. The rapid development of computational fluid dynamics has laid a solid material foundation for VAWT. Thus the static characteristics of the LDCS with different numbers of blades were investigated by conducting numerical simulation and wind tunnel tests. The results demonstrated that the static torque coefficient of LDCS increased significantly with the increased incoming wind speed. The average value of the static torque coefficient also increased significantly. This study can provide guidelines for the research of lift-drag combined wind turbines.


Wind Energy ◽  
2010 ◽  
Vol 13 (8) ◽  
pp. 727-736
Author(s):  
Chun-Ping Yeh ◽  
Weng-Sing Hwang

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