Aerodynamic and Structural Strategies for the Rotor Design of a Wind Turbine Scaled Model

Experimental tests performed in a wind tunnel or in a natural laboratory represent a fundamental research tool to develop floating wind technologies. In order to obtain reliable results, the wind turbine scale model rotor must be designed so to obtain a fluid-structure interaction comparable to the one experienced by a real machine. This implies an aerodynamic design of the 3D blade geometry but, also, a structural project to match the main aeroelastic issues. For natural laboratory models, due to not controlled test conditions, the wind turbine rotor model must be checked also for extreme winds. The present paper will focus on all the strategies adopted to scale a wind turbine blade presenting two studied cases: the first is a 1:75 scale model for wind tunnel applications and the second a 1:15 model for natural laboratory tests.

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How realistic are the wakes of scaled wind turbine models?

10.5194/wes-2020-115 ◽

2020 ◽

Author(s):

Chengyu Wang ◽

Filippo Campagnolo ◽

Helena Canet ◽

Daniel J. Barreiro ◽

Carlo L. Bottasso

Keyword(s):

Wind Tunnel ◽

Wind Turbine ◽

Inner Core ◽

Detailed Comparison ◽

Full Scale ◽

Scaling Analysis ◽

Scaled Model ◽

Eddy Simulation ◽

The One ◽

Physical Phenomena

Abstract. The aim of this paper is to analyze to which extent wind tunnel experiments can represent the behavior of full-scale wind turbine wakes. The question is relevant because on the one hand scaled models are extensively used for wake and farm control studies, whereas on the other hand not all wake-relevant physical characteristics of a full-scale turbine can be exactly matched by a scaled model. In particular, a detailed scaling analysis reveals that the scaled model accurately represents the principal physical phenomena taking place in the outer shell of the near wake, whereas differences exist in its inner core. A large eddy simulation actuator line method is first validated with respect to wind tunnel measurements, and then used to perform a detailed comparison of the wake at the two scales. It is concluded that, notwithstanding the existence of some mismatched effects, the scaled wake is remarkably similar to the full-scale one, except in the immediate proximity of the rotor.

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How realistic are the wakes of scaled wind turbine models?

Wind Energy Science ◽

10.5194/wes-6-961-2021 ◽

2021 ◽

Vol 6 (3) ◽

pp. 961-981

Author(s):

Chengyu Wang ◽

Filippo Campagnolo ◽

Helena Canet ◽

Daniel J. Barreiro ◽

Carlo L. Bottasso

Keyword(s):

Wind Tunnel ◽

Wind Turbine ◽

Inner Core ◽

Full Scale ◽

Scaling Analysis ◽

Scaled Model ◽

Eddy Simulation ◽

The One ◽

Scaled Models ◽

Physical Phenomena

Abstract. The aim of this paper is to analyze to which extent wind tunnel experiments can represent the behavior of full-scale wind turbine wakes. The question is relevant because on the one hand scaled models are extensively used for wake and farm control studies, whereas on the other hand not all wake-relevant physical characteristics of a full-scale turbine can be exactly matched by a scaled model. In particular, a detailed scaling analysis reveals that the scaled model accurately represents the principal physical phenomena taking place in the outer shell of the near wake, whereas differences exist in its inner core. A large-eddy simulation actuator-line method is first validated with respect to wind tunnel measurements and then used to perform a thorough comparison of the wake at the two scales. It is concluded that, notwithstanding the existence of some mismatched effects, the scaled wake is remarkably similar to the full-scale one, except in the immediate proximity of the rotor.

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Effects of Inflow Shear on Wake Characteristics of Wind-Turbines over Flat Terrain

Energies ◽

10.3390/en13143745 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3745 ◽

Cited By ~ 1

Author(s):

Takanori Uchida

Keyword(s):

Wind Tunnel ◽

Wind Turbine ◽

Wind Turbines ◽

Turbine Rotor ◽

Wind Tunnel Experiment ◽

Scale Model ◽

Speed Ratio ◽

Flat Terrain ◽

Wind Turbine Rotor ◽

Wake Characteristics

The scope of the present study was to understand the wake characteristics of wind-turbines under various inflow shears. First, in order to verify the prediction accuracy of the in-house large-eddy simulation (LES) solver, called RIAM-COMPACT, based on a Cartesian staggered grid, we conducted a wind-tunnel experiment using a wind-turbine scale model and compared the numerical and experimental results. The total number of grid points in the computational domain was about 235 million. Parallel computation based on a hybrid LES/actuator line (AL) model approach was performed with a new SX-Aurora TSUBASA vector supercomputer. The comparison between wind-tunnel experiment and high-resolution LES results showed that the AL model implemented in the in-house LES solver in this study could accurately reproduce both performances of the wind-turbine scale model and flow characteristics in the wake region. Next, with the LES solver developed in-house, flow past the entire wind-turbine, including the nacelle and the tower, was simulated for a tip-speed ratio (TSR) of 4, the optimal TSR. Three types of inflow shear, N = 4, N = 10, and uniform flow, were set at the inflow boundary. In these calculations, the calculation domain in the streamwise direction was very long, 30.0 D (D being the wind-turbine rotor diameter) from the center of the wind-turbine hub. Long-term integration of t = 0 to 400 R/Uin was performed. Various turbulence statistics were calculated at t = 200 to 400 R/Uin. Here, R is the wind-turbine rotor radius, and Uin is the wind speed at the hub-center height. On the basis of the obtained results, we numerically investigated the effects of inflow shear on the wake characteristics of wind-turbines over a flat terrain. Focusing on the center of the wind-turbine hub, all results showed almost the same behavior regardless of the difference in the three types of inflow shear.

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Performance prediction of loop-type wind turbine

Advances in Mechanical Engineering ◽

10.1177/1687814019840472 ◽

2020 ◽

Vol 12 (2) ◽

pp. 168781401984047

Author(s):

Wonyoung Jeon ◽

Jeanho Park ◽

Seungro Lee ◽

Youngguan Jung ◽

Yeesock Kim ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Tunnel ◽

Wind Turbine ◽

Experimental Results ◽

Scale Model ◽

Dynamics Analysis ◽

Blockage Ratio ◽

Horizontal Axis Wind Turbine ◽

Computational Fluid Dynamics Analysis

An experimental and analytical method to evaluate the performance of a loop-type wind turbine generator is presented. The loop-type wind turbine is a horizontal axis wind turbine with a different shaped blade. A computational fluid dynamics analysis and experimental studies were conducted in this study to validate the performance of the computational fluid dynamics method, when compared with the experimental results obtained for a 1/15 scale model of a 3 kW wind turbine. Furthermore, the performance of a full sized wind turbine is predicted. The computational fluid dynamics analysis revealed a sufficiently large magnitude of external flow field, indicating that no factor influences the flow other than the turbine. However, the experimental results indicated that the wall surface of the wind tunnel significantly affects the flow, due to the limited cross-sectional size of the wind tunnel used in the tunnel test. The turbine power is overestimated when the blockage ratio is high; thus, the results must be corrected by defining the appropriate blockage factor (the factor that corrects the blockage ratio). The turbine performance was corrected using the Bahaj method. The simulation results showed good agreement with the experimental results. The performance of an actual 3 kW wind turbine was also predicted by computational fluid dynamics.

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Aerodynamic Design of a Small-Scale Model of a Vertical Axis Wind Turbine

Proceedings ◽

10.3390/proceedings2231465 ◽

2018 ◽

Vol 2 (23) ◽

pp. 1465 ◽

Cited By ~ 1

Author(s):

Andrés Meana-Fernández ◽

Jesús Manuel Fernández Oro ◽

Katia María Argüelles Díaz ◽

Mónica Galdo-Vega ◽

Sandra Velarde-Suárez

Keyword(s):

Wind Tunnel ◽

Wind Turbine ◽

Vertical Axis ◽

Scale Model ◽

Small Scale ◽

Wind Tunnel Testing ◽

Aerodynamic Design ◽

Vertical Axis Wind Turbine ◽

Small Scale Model ◽

Tunnel Testing

Wind tunnel testing of small-scale models is one of the most useful techniques to predict the performance of real-scale applications. In this work, the aerodynamic design and the construction of a small-scale model of a straight-bladed vertical axis wind turbine for wind tunnel testing has been performed. Using a double multiple streamtube model (DMST), different solidity values for the turbine and different airfoil geometries were compared to select the final design. Once an optimal design was selected, a numerical simulation using Computational Fluid Dynamics (CFD) was performed in order to obtain a more precise description of the flow field as well as the performance of the model. Future work will comprise the characterization of the model and the comparison of the experimental and numerical results.

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The wind tunnel measuring methods for wind turbine rotor blades

Wind and Structures ◽

10.12989/was.2004.7.5.305 ◽

2004 ◽

Vol 7 (5) ◽

pp. 305-316 ◽

Cited By ~ 4

Author(s):

Ali Vardar ◽

Bulent Eker

Keyword(s):

Wind Tunnel ◽

Wind Turbine ◽

Turbine Rotor ◽

Rotor Blades ◽

Measuring Methods ◽

Wind Turbine Rotor

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Experimental Testing of a Wind Tunnel Model for Use in a Vertical Axis Wind Turbine

Volume 1: Advances in Aerospace Technology ◽

10.1115/imece2010-38816 ◽

2010 ◽

Cited By ~ 2

Author(s):

Chad C. Panther ◽

Kenny A. Williams ◽

Jay P. Wilhelm ◽

James E. Smith

Keyword(s):

Wind Tunnel ◽

Rapid Prototyping ◽

Wind Turbine ◽

Model Building ◽

Experimental Testing ◽

Vertical Axis ◽

Scale Model ◽

Circulation Control ◽

Vertical Axis Wind Turbine ◽

Trailing Edge

Experimental testing was performed on a circulation controlled airfoil with upper and lower trailing edge blowing slots, controlled by span wise pneumatic valves. The augmented blade was designed for application to a circulation controlled vertical axis wind turbine. The design is based upon a conventional NACA0018 shape, replacing the sharp trailing edge with a rounded Coanda surface and blowing slots. A scale model with a chord of 8 inches and span of 16.5 inches was created using an ABS plastic rapid prototyping machine. In the past, circulation control wind tunnel models have been constructed with a separate blowing slot and trailing edge using conventional machining methods. The slot must be tediously aligned along the span for a consistent height which ultimately affects the uniformity and performance of the circulation control jet in combination with the flow rate. The rapid prototyping machine eased fabrication as a modular trailing edge section was printed which includes the Coanda surface, blowing slot, and diffuser all in one piece. Pressure taps were integrated by the prototyping machine into both the printed skin and trailing edge module. This method left additional space inside the model for circulation control valving components and eliminated the need for machining pressure ports. This paper will outline the model building procedures, wind tunnel test rig, and experimental results. Aerodynamic forces were determined by both load cells and surface pressure measurements; the agreement between the two methods will be analyzed and addressed. Test conditions include various angles of attack (±20°) at Cμ = 0, 0.02, 0.06, and 0.10; the test Reynolds number was kept constant at 300K. The results indicate that the blade performed at ΔCl/Cμ near 30 for Cμ = 0.02.

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Blockage effect correction for a scaled wind turbine rotor by using wind tunnel test data

Renewable Energy ◽

10.1016/j.renene.2014.11.057 ◽

2015 ◽

Vol 79 ◽

pp. 227-235 ◽

Cited By ~ 27

Author(s):

Jaeha Ryi ◽

Wook Rhee ◽

Ui Chang Hwang ◽

Jong-Soo Choi

Keyword(s):

Wind Tunnel ◽

Wind Turbine ◽

Test Data ◽

Wind Tunnel Test ◽

Turbine Rotor ◽

Wind Turbine Rotor ◽

Blockage Effect

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Experimental and Numerical Analysis of a Seawall’s Effect on Wind Turbine Performance

Energies ◽

10.3390/en12203877 ◽

2019 ◽

Vol 12 (20) ◽

pp. 3877 ◽

Cited By ~ 1

Author(s):

Hyun-Goo Kim ◽

Wan-Ho Jeon

Keyword(s):

Numerical Analysis ◽

Wind Speed ◽

Wind Tunnel ◽

Wind Turbine ◽

Flow Separation ◽

Wind Farm ◽

Wind Tunnel Experiment ◽

Scale Model ◽

Wind Flow ◽

Cfd Analysis

For the purposes of this study, a wind tunnel experiment and a numerical analysis during ebb and high tides were conducted to determine the positive and negative effects of wind flow influenced by a seawall structure on the performance of wind turbines installed along a coastal seawall. The comparison of the wind flow field between a wind tunnel experiment performed with a 1/100 scale model and a computational fluid dynamics (CFD) analysis confirmed that the MP k-turbulence model estimated flow separation on the leeside of the seawall the most accurately. The CFD analysis verified that wind speed-up occurred due to the virtual hill effect caused by the seawall’s windward slope and the recirculation zone of its rear face, which created a positive effect by mitigating wind shear while increasing the mean wind speed in the wind turbine’s rotor plane. In contrast, the turbulence effect of flow separation on the seawall’s leeside was limited to the area below the wind turbine rotor, and had no negative effect. The use of the CFD verified with the comparison with the wind tunnel experiment was extended to the full-scale seawall, and the results of the analysis based on the wind turbine Supervisory Control and Data Acquisition (SCADA) data of a wind farm confirmed that the seawall effect was equivalent to a 1.5% increase in power generation as a result of a mitigation of the wind profile.

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