scholarly journals Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind turbine arrays

2011 ◽  
Vol 3 (4) ◽  
pp. 043104 ◽  
Author(s):  
John O. Dabiri
Keyword(s):  
Wind Turbine ◽  
Power Density ◽  
Wind Farm ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Order Of Magnitude ◽  
Turbine Arrays

scholarly journals Flow Characteristics of a Straight-Bladed Vertical Axis Wind Turbine with Inclined Pitch Axes

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6281
Author(s):  
Jia Guo ◽  
Liping Lei
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Flow Characteristics ◽  
Wind Farms ◽  
Vertical Axis ◽  
Incline Angle ◽  
Vertical Axis Wind Turbine ◽  
Unsteady Wake ◽  
Horizontal Axis Wind Turbines

Currently, vertical axis wind turbines (VAWT) are considered as an alternative technology to horizontal axis wind turbines in specific wind conditions, such as offshore farms. However, complex unsteady wake structures of VAWTs exert a significant influence on performance of wind turbines and wind farms. In the present study, instantaneous flow fields around and downstream of an innovative VAWT with inclined pitch axes are simulated by an actuator line model. Unsteady flow characteristics around the wind turbine with variations of azimuthal angles are discussed. Several fluid parameters are then evaluated on horizontal and vertical planes under conditions of various fold angles and incline angles. Results show that the total estimated wind energy in the shadow of the wind turbine with an incline angle of 30° and 150° is 4.6% higher than that with an incline angle of 90°. In this way, appropriate arrangements of wind turbines with various incline angles have the potential to obtain more power output in a wind farm.

Swept Blade for Performance Improvement on a Vertical Axis Wind Turbine

2020 ◽  
Author(s):  
Jie Su ◽  
Yaoran Chen ◽  
Dai Zhou ◽  
Zhaolong Han ◽  
Yan Bao
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Static Pressure Distribution ◽  
Low Wind Speed ◽  
Turbine Wake ◽  
Wind Turbine Wake

Abstract The vertical axis wind turbine (VAWT) is considered an important device to utilize the renewable and sustainable wind energy. However, the relatively lower power coefficient has hampered its development. Therefore, this paper attempts to investigate the effect of swept blade employed in a VAWT on the enhancement in aerodynamic performance. A series of swept blades were studied in a small VAWT rotor, and the RANS SST k-ω turbulence model was utilized to simulate the flow field. The numerical model was validated against experimental data, and the aerodynamic performance was investigated with respect to force coefficients, vorticity distribution, static pressure distribution, and wind turbine wake, respectively. The results indicated that the swept blade could effectively increase power outputs by about 20% for the wind turbine. By reducing the drag coefficient, a high lift-drag ratio was achieved. And this configuration prevented the blade from suffering severe dynamic stall. Besides, the swept blade changed the distribution of low wind speed area in the wind turbine wake, which should be considered in the wind farm. It was concluded that this work provided a new way for the practical design and optimization of wind turbine.

scholarly journals Vertical-axis wind-turbine computations using a 2D hybrid wake actuator-cylinder model

2021 ◽  
Author(s):  
Edgar Alejandro Martinez-Ojeda ◽  
Francisco Javier Solorio Ordaz ◽  
Mihir Sen
Keyword(s):  
Wind Turbine ◽  
Hollow Cylinder ◽  
Wind Farm ◽  
Finite Thickness ◽  
Vertical Axis ◽  
Small Scale ◽  
Computational Domain ◽  
Source Terms ◽  
Vertical Axis Wind Turbine ◽  
Cylinder Model

Abstract. The actuator-cylinder model was implemented in OpenFOAM by virtue of source terms in the Navier-Stokes equations. Since the stand-alone actuator cylinder is not able to properly model the wake of a vertical-axis wind turbine, the steady incompressible flow solver SimpleFoam provided by OpenFOAM was used to resolve the entire flow and wakes of the turbines. The source terms are only applied inside a certain region of the computational domain, namely a finite thickness cylinder which represents the flight path of the blades. One of the major advantages of this approach is its implicitness, that is, the velocities inside the hollow cylinder region feed the actuator-cylinder model, this in turn computes the volumetric forces and passes them to the OpenFOAM solver in order to be applied inside the hollow cylinder region. The process is repeated in each iteration of the solver until convergence is achieved. The hybrid RANS actuator-cylinder can be used to model a wind farm since a turbine is now able to take into account the effect of other wakes. The model was compared against numerical and experimental works, wake deficits and power coefficients are used in order to assess the validity of the model. Overall, there is a good agreement of the pattern of the power coefficients according to the positions of the turbines in the array. Wake patterns are also similar at certain distances downwind. The actual accuracy of the power coefficient depends strongly on the solidity of the turbine (actuator-cylinder related) and the inlet boundary turbulence intensity (RANS simulation related); a heuristic approach to correct the results of high-solidity turbines is presented for the case of a wind farm made of small-scale turbines. Thus this method can be used to quickly compute the power coefficients of low-solidity vertical-axis wind farms.

scholarly journals Development of a parameterized reduced-order vertical-axis wind turbine wake model

2019 ◽  
Vol 44 (5) ◽  
pp. 494-508 ◽  
Author(s):  
Eric B Tingey ◽  
Andrew Ning
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Computational Cost ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Reduced Order ◽  
Wake Interactions ◽  
Wake Model ◽  
Turbine Wake

Analyzing or optimizing wind farm layouts often requires reduced-order wake models to estimate turbine wake interactions and wind velocity. We propose a wake model for vertical-axis wind turbines in streamwise and crosswind directions. Using vorticity data from computational fluid dynamic simulations and cross-validated Gaussian distribution fitting, we produced a wake model that can estimate normalized wake velocity deficits of an isolated vertical-axis wind turbine using normalized downstream and lateral positions, tip-speed ratio, and solidity. Compared with computational fluid dynamics, taking over a day to run one simulation, our wake model predicts a velocity deficit in under a second with an appropriate accuracy and computational cost necessary for wind farm optimization. The model agreed with two experimental studies producing percent differences of the maximum wake deficit of 6.3% and 14.6%. The wake model includes multiple wake interactions and blade aerodynamics to calculate power, allowing its use in wind farm layout analysis and optimization.

Calculating the aerodynamics of vertical axis wind turbines

2012 ◽  
Vol 34 (3) ◽  
pp. 169-184 ◽  
Author(s):  
Hoang Thi Bich Ngoc
Keyword(s):  
Wind Turbine ◽  
Incidence Angle ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Velocity Triangle ◽  
Relationship Of ◽  
The Relationship

Vertical axis wind turbine technology has been applied last years, very long after horizontal axis wind turbine technology. Aerodynamic problems of vertical axis wind machines are discussible. An important problem is the determination of the incidence law in the interaction between wind and rotor blades. The focus of the work is to establish equations of the incidence depending on the blade azimuth, and to solve them. From these results, aerodynamic torques and power can be calculated. The incidence angle is a parameter of velocity triangle, and both the factors depend not only on the blade azimuth but also on the ratio of rotational speed and horizontal speed. The built computational program allows theoretically selecting the relationship of geometric parameters of wind turbine in accordance with requirements on power, wind speed and installation conditions.

Design and Analysis of Vertical Axis Wind Turbine

2017 ◽  
Author(s):  
Prof. R.K. Bhoyar ◽  
Prof. S.J. Bhadang ◽  
Prof. N.Z. Adakane ◽  
Prof. N.D. Pachkawade
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine
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