scholarly journals Aerodynamic characteristics of seven symmetrical airfoil sections through 180-degree angle of attack for use in aerodynamic analysis of vertical axis wind turbines

1981 ◽  
Author(s):  
R E Sheldahl ◽  
P C Klimas
Keyword(s):  
Wind Turbines ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Analysis ◽  
Vertical Axis Wind Turbines

Aerodynamic analysis of side-by-side placed twin vertical-axis wind turbines

2020 ◽  
Vol 209 ◽  
pp. 107296
Author(s):  
Guoqing Jin ◽  
Zhi Zong ◽  
Yichen Jiang ◽  
Li Zou
Keyword(s):  
Wind Turbines ◽  
Vertical Axis ◽  
Aerodynamic Analysis ◽  
Vertical Axis Wind Turbines

Aerodynamic Factors Affecting Performance of Straight-Bladed Vertical Axis Wind Turbines

2007 ◽  
Author(s):  
Mazharul Islam ◽  
M. Ruhul Amin ◽  
David S.-K. Ting ◽  
Amir Fartaj
Keyword(s):  
Experimental Data ◽  
Wind Turbines ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Factors Affecting ◽  
Vertical Axis Wind Turbines ◽  
Wide Range ◽  
Flow Curvature ◽  
Factors Affecting Performance

Unlike the conventional aerodynamic applications, the straight-bladed vertical axis wind turbines (VAWTs) operate in a circular motion and encounter a wide range of angle of attacks, especially at low tip speed ratios. When the blade angle of attack remains constant or varies slowly with time, it encounters the static stall. However, when the angle of attack changes rapidly with time, it experiences the dynamic stall which is far more difficult to analyze and predict than the static stall. Furthermore, the blade/blade wake interaction in straight-bladed VAWTs also presents modeling problem. In this paper, all of these aforesaid aerodynamic factors are discussed. It was found that these factors need special attention for designing a self-starting straight-bladed VAWT with optimum performance. A numerical method based on Cascade model, proposed by Hirsch and Mandal [1], that gives reasonable correlation with the experimental data available has been used. The effects of dynamic stall and flow curvature on the performance of a straight-bladed VAWT have been analyzed. It is observed from the analysis that aerodynamic forces due to dynamic stall are higher than those due to static stall. As a result, for the performance prediction of straight-bladed VAWTs, especially for the local forces, there can be substantial differences between the experimental data and the calculated values unless the dynamic stall effect is added.

A Robust Procedure to Implement Dynamic Stall Models Into Actuator Line Methods for the Simulation of Vertical-Axis Wind Turbines

2021 ◽  
Author(s):  
Pier Francesco Melani ◽  
Francesco Balduzzi ◽  
Alessandro Bianchini
Keyword(s):  
Flow Field ◽  
Wind Turbines ◽  
Signal To Noise Ratio ◽  
Angle Of Attack ◽  
Computational Cost ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Vertical Axis Wind Turbines ◽  
Lumped Parameter ◽  
Low Pass

Abstract The Actuator Line Method (ALM), combining a lumped-parameter representation of the rotating blades with the CFD resolution of the turbine flow field, stands out among the modern simulation methods for Vertical-Axis Wind Turbines (VAWTs) as probably the most interesting compromise between accuracy and computational cost. Being however a method relying on tabulated coefficients for modeling the blade-flow interaction, the correct implementation of the sub-models to account for higher order aerodynamic effects is pivotal. Inter alia, the introduction of a dynamic stall model is extremely challenging. As a matter of fact, two main issues arise: first, it is important to extrapolate a correct value of the angle of attack (AoA) from the CFD solved flow field; second, the AoA history required as an input to calculate the rate of dynamic variation of the angle itself is characterized by a low signal-to-noise ratio, leading to severe numerical oscillations of the solution. In the study, a robust procedure to improve the quality of the AoA signal extracted from an ALM simulation is introduced. The procedure combines a novel method for sampling of the inflow velocity from the numerical flow field with a low-pass filtering of the corresponding angle of attack signal based on Cubic Spline Smoothing (CSS). Such procedure has been implemented in the Actuator Line module developed by the authors for the commercial ANSYS® FLUENT® solver. In order to verify the reliability of the proposed methodology, two-dimensional unsteady RANS simulations of a test 2-blade Darrieus H-rotor, for which high-fidelity experimental and numerical blade loading data were available, have been eventually performed for a selected turbine unstable operation point.

The Aerodynamic Performance of Offshore Twin Vertical Axis Wind Turbines With Deflector

2019 ◽  
Author(s):  
Yichen Jiang ◽  
Peidong Zhao ◽  
Li Zou ◽  
Guiyong Zhang ◽  
Zhi Zong
Keyword(s):  
Wind Turbines ◽  
Dynamic Method ◽  
Fluid Dynamic ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Vertical Axis Wind Turbines ◽  
Simulation Results ◽  
Novel Design ◽  
Local Angle

Abstract A novel design of offshore twin counter-rotating vertical axis wind turbines (VAWTs) with deflector is proposed in this paper. We investigate the performance of the twin VAWTs by the two-dimensional computational fluid dynamic method with the Spalart-Allmaras turbulence model. Then, the performances of twin VAWTs with three kinds of deflectors are compared. The results show that installing the front deflector leads to significant improved aerodynamic performance. To better understand the simulation results, we introduce a simple and effective method to obtain the blade’s angle of attack. The mechanism of enhanced performance by deflector is pointed out, based on the information of the blade’s local angle of attack and flow field. Finally, a guideline on the design of deflector for the twin vertical axis wind turbines is provided.

CFD modeling of varying complexity for aerodynamic analysis of H-vertical axis wind turbines

2020 ◽  
Vol 145 ◽  
pp. 2658-2670 ◽  
Author(s):  
Jiao He ◽  
Xin Jin ◽  
Shuangyi Xie ◽  
Le Cao ◽  
Yaming Wang ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Vertical Axis ◽  
Cfd Modeling ◽  
Aerodynamic Analysis ◽  
Vertical Axis Wind Turbines
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