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

Sheldahl, Robert E.; Klimas, Paul C.

doi:10.2172/6548367

Cited by 648 publications

(612 citation statements)

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“…Initial analysis of 4 symmetrical NACA 4-digit foils [7] suggested that NACA 0018 had the best characteristics for vertical axis tidal current turbine. The NACA 0018 profile was chosen as the blade section with data from Sheldahl and Klimas [8]. This foil is commonly used for Darrieus turbines because it has relatively high thickness to chord ratio hence gives it good strength in bending.…”

Section: Experimental Modelmentioning

confidence: 99%

“…Mechanism to obtain the foil angle of freedom is based on the stall angle for NACA 0018 series [8]. Numerical validation at Re 80000 has been carried out [9] and provides the first stall at AoA of 10 0 , and the next is at AoA of 45 0 as shown in Figure 4.…”

Section: Obtaining Passive Variable-pitchmentioning

confidence: 99%

“…At AoA higher than this the aerofoil undergoes stall: the flow separate from the upper surface of the foil causing a loss of lift and an increase in drag [10]. Kirke and Lazauskas [8] provides the shifting of AoA due to increasing of Re ( Figure 5). The Re increment as a function of upstream velocity gives greater AoA to stall.…”

Section: Obtaining Passive Variable-pitchmentioning

confidence: 99%

See 2 more Smart Citations

An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine

Hantoro¹,

Utama²,

Erwandi³

et al. 2011

itbj.eng.sci.

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Abstract. Vertical-axis hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Maximizing the turbine power output can be achieved only if the mechanism of generation of the hydrodynamic force on the blades is clearly identified and tools to design high-performance rotors are developed. This paper describes an initial experimental investigation to understand more of the performance on vertical-axis turbine related to the effect of fixed-pitch and passive variable-pitch application using airfoil NACA 0018. Comparative analysis according to aspects of rotation and tip speed ratios was discussed. Information regarding the changes of foil position in passive variable-pitch during rotation at a limited range of flow velocity variations test was obtained and analyzed.

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Section: Experimental Modelmentioning

confidence: 99%

Section: Obtaining Passive Variable-pitchmentioning

confidence: 99%

Section: Obtaining Passive Variable-pitchmentioning

confidence: 99%

See 1 more Smart Citation

An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine

Hantoro¹,

Utama²,

Erwandi³

et al. 2011

itbj.eng.sci.

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“…12c at Re 700,000. Here the numerical data are compared to three different sets of experimental data by Timmer [46], by Sheldal [48] and by Jacobs [49]. The striking differences between the experimental data in incipient and deep stall conditions make the level of uncertainty of this kind of experimental measures clearly understandable.…”

Section: Resultsmentioning

confidence: 99%

Transition turbulence model calibration for wind turbine airfoil characterization through the use of a Micro-Genetic Algorithm

Mauro

Lanzafame

Messina

et al. 2017

Int J Energy Environ Eng

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The aerodynamic characterization of airfoils is of crucial importance for the design and optimization of wind turbines. The present paper tries to provide an engineering methodology for the improvement of the accuracy and reliability of 2D airfoil computational fluid dynamics models, by coupling the ANSYS Fluent solver and a Micro-Genetic Algorithm. The modeling strategy provided includes meshing optimization, solver settings, comparison between different turbulence models and, mainly, the calibration of the local correlation parameters of the transition turbulence model by Menter, which was found to be the most accurate model for the simulation of transitional flows. Specifically, the Micro-Genetic Algorithm works by generating populations of the missing local correlation parameters. In doing so, it is possible to search for the minimization of the error in lift calculations. For each specific Reynolds number, the calibration was carried out only at the Angle of Attack where the lift drop occurs and the airfoil completely stalls. This new idea allowed for a relatively rapid and good calibration as demonstrated by the experimental-numerical comparisons presented in this paper. Only the experimental stall angle and the relative lift coefficient were, therefore, necessary for obtaining a good calibration. The calibration was made using the widely known S809 profile data. The correlation parameters, obtained as so, were subsequently used for testing on the NACA 0018 airfoil with satisfactory results. Therefore, the calibration obtained using the S809 airfoil data appeared to be reliable and may be used for the simulation of other airfoils. This can be done without the need for further wind tunnel experimental data or recalibrations. The proposed methodology will, therefore, be of essential help in obtaining accurate aerodynamic coefficients data. This will drastically improve the capabilities of the 1D design codes at low Reynolds numbers thanks to the possibility of generating accurate databases of 2D airfoil aerodynamic coefficients. The advantages of the proposed calibration will be helpful in the generation of more accurate 3D wind turbine models as well. The final objective of the paper was thus to obtain a fine and reliable calibration of the transition turbulence model by Menter. This was specifically made for an accurate prediction of the aerodynamic coefficients of any airfoil at low Reynolds numbers and for the improvements of 3D rotor models.

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“…The lift, drag and pitching moment of each element are calculated numerically using nonlinear look-up tables as functions of angle of attack and Reynolds number. Experimental data for a NACA0015 aerofoil section are used for each blade element [42]; since it is of interest to investigate the high advance ratio condition, in which reverse flow is expected to occur over a portion of the rotor disc, the look-up tables cover the whole 360 • range of angle of attack. -Unsteady flow and vortex shedding effects ignored.…”

Section: Description Of Rotor Modelmentioning

confidence: 99%

On the nonlinear dynamics of a rotor in autorotation: a combined experimental and numerical approach

Rezgui¹,

Lowenberg

2015

Phil. Trans. R. Soc. A.

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One contribution of 11 to a theme issue 'A field guide to nonlinearity in structural dynamics' . This article presents a systematic assessment of the use of numerical continuation and bifurcation techniques in investigating the nonlinear periodic behaviour of a teetering rotor operating in forward autorotation. The aim is to illustrate the potential of these tools in revealing complex blade dynamics, when used in combination (not necessarily at the same time) with physical testing. We show a simple procedure to promote understanding of an existing but not fully understood engineering instability problem, when uncertainties in the numerical modelling and constraints in the experimental testing are present. It is proposed that continuation and bifurcation methods can play a significant role in developing numerical and experimental techniques for studying the nonlinear dynamics not only for rotating blades but also for other engineering systems with uncertainties and constraints.

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

Cited by 648 publications

References 0 publications

An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine

An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine

Transition turbulence model calibration for wind turbine airfoil characterization through the use of a Micro-Genetic Algorithm

On the nonlinear dynamics of a rotor in autorotation: a combined experimental and numerical approach

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