Unsteady Flow Simulation and Dynamic Stall Behaviour of Vertical Axis Wind Turbine Blades

Qin, Ning; Howell, Robert J.; Durrani, Naveed; Hamada, Kenichi; Smith, Tomos

doi:10.1260/0309-524x.35.4.511

Cited by 57 publications

(29 citation statements)

References 10 publications

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“…In this paper, ANSYS Fluent 15.0 (ANSYS, Canonsburg, PA, USA) and Tecplot 360 R1 (Tecplot 360 R1 2013, Tecplot, Bellevue, WA, USA) were adopted in the CFD simulations and post-processing. From the references of [20][21][22][23], the results computed by the unsteady RANS model is consistent with the data measured by LDV. Therefore, the shear-stress transport (SST) k-ω turbulence model is applied in CFD simulations in this study.…”

Section: Theory and Numerical Methodssupporting

confidence: 78%

“…In this study, the evolution of the flow field was not only affected by the variations of the angle of attack, but also by the formation, roll-up, release and interaction of the shedding vortex. In order to investigate the subtle changes of dynamic stall, Qin et al [20] in 2011 computed the evolution of the dynamic stall of rotor in the condition of low-to-moderate Reynolds number, based on the unsteady Reynolds-averaged Navier-Stokes (RANS) equations. In this study, they found that the model not only saved computation time, but also improved the precision of the CFD simulations.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation of the Tip Vortex of a Straight-Bladed Vertical Axis Wind Turbine with Double-Blades

et al. 2017

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Abstract:Wind velocity distribution and the vortex around the wind turbine present a significant challenge in the development of straight-bladed vertical axis wind turbines (VAWTs). This paper is intended to investigate influence of tip vortex on wind turbine wake by Computational Fluid Dynamics (CFD) simulations. In this study, the number of blades is two and the airfoil is a NACA0021 with chord length of c = 0.265 m. To capture the tip vortex characteristics, the velocity fields are investigated by the Q-criterion iso-surface (Q = 100) with shear-stress transport (SST) k-ω turbulence model at different tip speed ratios (TSRs). Then, mean velocity, velocity deficit and torque coefficient acting on the blade in the different spanwise positions are compared. The wind velocities obtained by CFD simulations are also compared with the experimental data from wind tunnel experiments. As a result, we can state that the wind velocity curves calculated by CFD simulations are consistent with Laser Doppler Velocity (LDV) measurements. The distribution of the vortex structure along the spanwise direction is more complex at a lower TSR and the tip vortex has a longer dissipation distance at a high TSR. In addition, the mean wind velocity shows a large value near the blade tip and a small value near the blade due to the vortex effect.

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Section: Theory and Numerical Methodssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Tip Vortex of a Straight-Bladed Vertical Axis Wind Turbine with Double-Blades

et al. 2017

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“…The power coefficient of the RNG k-ε model is comparatively close to the experimental value. Qin et al (2011) reported that the predicted torque of the VAWT with fixed-pitch straight blades obtained by using the Realizable k- model was much higher than that when using the RNG k- model. The Realizable k- model has a limitation to produce non-physical turbulent viscosities when the computational domain contains both rotating and stationary fluid zones (ANSYS Theory Guide, 2012).…”

Section: Evaluation Of the Turbulence Model In Numerical Simulationsmentioning

confidence: 97%

Numerical and experimental studies of a small vertical-axis wind turbine with variable-pitch straight blades

Firdaus

Kiwata

Kono

et al. 2015

JFST

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This paper presents a numerical simulation and experiment on the effect of the variable pitch angle on the performance of a small vertical-axis wind turbine (VAWT) with straight blades. The power coefficient of the VAWT was measured in an open-circuit wind tunnel. By conducting two-dimensional unsteady computational fluid dynamics simulations using the RNG k-ε, Realizable k-ε, and SST k-ω models, the power and torque of the VAWT and the flow around the straight blades were also analyzed. The numerical simulation of the power performance results were validated using wind tunnel experimental data. The results of both the numerical simulations and experiments showed that a VAWT with variable-pitch blades has better performance than a VAWT with fixed-pitch blades. The numerical simulation of the performance using the RNG k-ε turbulence model had good qualitative agreement with the experimental results. The numerical simulation was able to capture the flow separation on a blade, and it was shown that a variable-pitch blade can suppress the flow separation on its blades at a tip speed ratio lower than that of fixed-pitch blades. with the NACA0018 can be further improved by setting the wings at an outward angle of 5 degrees. Yamada et al. (2011) have also studied the effects of the camber and thickness of a blade (NACA0020, 3520, 6518, 6520, 6525, 6530, and 8520) on the performance of a small straight-bladed VAWT. Their report showed the mean and temporal torque variation at any azimuth angle of one and two blades.As part of a numerical simulation, Chen and Kuo (2013) have studied the effects of pitch angle and blade camber on the unsteady flow characteristics and the performance of a small-size Darrieus wind turbine with the NACA0012, 2412, and 4412 blade profiles. Their results indicated that the self-starting ability and the moment coefficients of a VAWT that has blades with large cambers (NACA4412) are better than those with the other blades (NACA0012 and 2412). Chen and Zhou (2009) used the SST k-ω model to investigate the aerodynamic performance of a VAWT via a two-dimensional numerical simulation. The results showed the optimum pitch angle for the power coefficient of the VAWT. Aresti et al. (2013) conducted two-and three-dimensional numerical simulations of the performance and flow through a small scale H-type Darrieus wind turbine by using the RNG k-ε, standard k-ε, and standard k-ω turbulence models. The self-starting capabilities of the VAWT were found to increase with the increasing mount angle of attack of the blades. Almohammadi et al. (2013) investigated the mesh independence of the predicted power coefficient of a VAWT with straight blades by employing a two-dimensional numerical simulation. Roh and Kang (2013) investigated the effects of a blade profile, the Reynolds number, and the solidity on the performance of a straight-bladed VAWT by using the numerical procedure of the multiple stream tube method. McNaughton et al. (2014) presented a two-dimensional numerical investigation of a VAWT, wh...

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“…The unsteady blade flow physics have been investigated by Martinat [4] and Wang [5] by simulating the flow around an airfoil with rapid changes in angel of attack. Research performed by Qin [6] studied the dynamic stall characteristics of VAWT blade. PIV studies conducted by Ferreira [7] revealed complex mechanisms of dynamic stall phenomenon of VAWT blade.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Flow Field and Aerodynamic Performance of Straight Bladed VAWT at Variable Tip Speed Ratios

Mei¹,

Qu²

2015

TOMEJ

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This paper studies the relationship between unsteady flow features and instantaneous torque and power performance of straight bladed vertical axis wind turbine at variable tip speed ratios. The rotor unsteady flow field simulation was carried out by using computational fluid dynamics method. The flow physics and the principle of changing flow filed acting on torque performance and power performance has been analyzed where the rotating rotor was the major concern. The results show that the flow feature alters from periodical blade dynamic stall vortexes generation, development and shedding at low tip speed ratio to cyclical formation, evolution and diffusion of blade wake flow with the rising tip speed ratio. Both vortex shedding around the blade and interaction of blade wakes degrade the rotor aerodynamic performance. It is suggested that, to absorbing the maximum wind energy, delaying the blade vortex shedding and reducing the range of blade wake evolution and diffusion should be included in the rotor aerodynamic design.

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Unsteady Flow Simulation and Dynamic Stall Behaviour of Vertical Axis Wind Turbine Blades

Cited by 57 publications

References 10 publications

Numerical Investigation of the Tip Vortex of a Straight-Bladed Vertical Axis Wind Turbine with Double-Blades

Numerical Investigation of the Tip Vortex of a Straight-Bladed Vertical Axis Wind Turbine with Double-Blades

Numerical and experimental studies of a small vertical-axis wind turbine with variable-pitch straight blades

Numerical Study of Flow Field and Aerodynamic Performance of Straight Bladed VAWT at Variable Tip Speed Ratios

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