scholarly journals Estimating the angle of attack from blade pressure measurements on the National Renewable Energy Laboratory phase VI rotor using a free wake vortex model: yawed conditions

Wind Energy ◽  
2009 ◽  
Vol 12 (1) ◽  
pp. 1-32 ◽  
Author(s):  
Tonio Sant ◽  
Gijs van Kuik ◽  
G. J. W. van Bussel
Keyword(s):  
Renewable Energy ◽  
Angle Of Attack ◽  
Wake Vortex ◽  
National Renewable Energy Laboratory ◽  
Pressure Measurements ◽  
Vortex Model ◽  
Free Wake

scholarly journals A Modified Free Wake Vortex Ring Method for Horizontal-Axis Wind Turbines

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3900 ◽  
Author(s):  
Jing Dong ◽  
Axelle Viré ◽  
Carlos Simao Ferreira ◽  
Zhangrui Li ◽  
Gerard van Bussel
Keyword(s):  
Wind Turbine ◽  
Vortex Ring ◽  
Horizontal Axis ◽  
Wake Vortex ◽  
Horizontal Axis Wind Turbine ◽  
Vortex Model ◽  
Ring Method ◽  
Wake Model ◽  
Free Wake ◽  
Platform Motions

A modified free-wake vortex ring model is proposed to compute the dynamics of a floating horizontal-axis wind turbine, which is divided into two parts. The near wake model uses a blade bound vortex model and trailed vortex model, which is developed based on vortex filament method with straight lifting lines assumption. By contrast, the far wake model is based on the vortex ring method. The proposed model is a good compromise between accuracy and computational cost, for example when compared with more complex vortex methods. The present model is used to assess the influence of floating platform motions on the performance of a horizontal-axis wind turbine rotor. The results are validated on the 5 MW NREL rotor and compared with other aerodynamic models for the same rotor subjected to different platform motions. The results show that the proposed method is reliable. In addition, the proposed method is less time consuming and has similar accuracy when comparing with more advanced vortex based methods.

Extension of a Helicoidal Vortex Model to Account for Blade Flexibility and Tower Interference

2006 ◽  
Vol 128 (4) ◽  
pp. 455-460 ◽  
Author(s):  
Jean-Jacques Chattot
Keyword(s):  
Experimental Data ◽  
Renewable Energy ◽  
Wind Tunnel ◽  
Vortex Method ◽  
Flow Speed ◽  
National Renewable Energy Laboratory ◽  
Incoming Flow ◽  
Bending Moments ◽  
Vortex Model ◽  
Potential Sources

The unsteady vortex method has been extended to account for blade flexibility and tower interference. These are two potential sources of unsteadiness of the flow past a wind turbine blade. The cases presented correspond to an incoming flow speed V=5m∕s and low yaw angles and V=8, 10, and 12m∕s and zero yaw. Comparisons of the root flap bending moments predicted by the model with the National Renewable Energy Laboratory (NREL) experimental data indicate that the NREL blades designed for the wind tunnel campaigns are quite rigid and that the tower interference is responsible for unsteadiness that is well captured by the model for zero yaw as well as for yaw of 5, 10 and 20deg.

scholarly journals Dynamic prescribed-wake vortex method for aerodynamic analysis of offshore floating wind turbines

2018 ◽  
Vol 43 (1) ◽  
pp. 47-63
Author(s):  
Jeanie Aird ◽  
Evan Gaertner ◽  
Matthew Lackner
Keyword(s):  
Vortex Method ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wake Vortex ◽  
Analysis Tool ◽  
Vortex Model ◽  
Comparable Accuracy ◽  
Wake Model ◽  
Turbine Design ◽  
Free Wake

A prescribed-wake vortex model for evaluating the aerodynamic loads on offshore floating turbines has been developed. As an extension to the existing UMass analysis tool, WInDS, the developed model uses prescribed empirical wake node velocity functions to model aerodynamic loading. This model is applicable to both dynamic flow conditions and dynamic rotational and translational platform motions of floating offshore turbines. With this model, motion-induced wake perturbations can be considered, and their effect on induction can be modeled, which is useful for floating offshore wind turbine design. The prescribed-wake WInDS model is shown to increase computational efficiency drastically in all presented cases and maintain comparable accuracy to the free wake model. Results of prescribed-wake model simulations are presented and compared to results obtained from the free wake model to confirm model validity.

Influence of Rigid Body Motions on Rotor Induced Velocities and Aerodynamic Loads of a Floating Horizontal Axis Wind Turbine

2014 ◽  
Author(s):  
Jacobus B. de Vaal ◽  
Martin O. L. Hansen ◽  
Torgeir Moan
Keyword(s):  
Rigid Body ◽  
Wind Turbine ◽  
Horizontal Axis ◽  
Simplified Model ◽  
Wake Vortex ◽  
Horizontal Axis Wind Turbine ◽  
Aerodynamic Loads ◽  
Vortex Model ◽  
Rigid Body Motions ◽  
Free Wake

This paper discusses the influence of rigid body motions on rotor induced velocities and aerodynamic loads of a floating horizontal axis wind turbine. Analyses are performed with a simplified free wake vortex model specifically aimed at capturing the unsteady and non-uniform inflow typically experienced by a floating wind turbine. After discussing the simplified model in detail, comparisons are made to a state of the art free wake vortex code, using test cases with prescribed platform motion. It is found that the simplified model compares favourably with a more advanced numerical model, and captures the essential influences of rigid body motions on the rotor loads, induced velocities and wake influence.

A Modified Free-Wake Vortex Ring Model for the Aerodynamics of Floating Offshore Wind Turbines

2019 ◽  
Author(s):  
Jing Dong ◽  
Axelle Viré ◽  
Simao Ferreira ◽  
Zhangrui Li ◽  
Gerard van Bussel
Keyword(s):  
Wind Turbine ◽  
Vortex Ring ◽  
Horizontal Axis ◽  
Wake Vortex ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Vortex Model ◽  
Ring Model ◽  
Wake Model ◽  
Free Wake

Abstract A modified free-wake vortex ring model is proposed to compute the dynamics of a floating horizontal-axis wind turbine. The model is divided into two parts. The near wake model uses a blade bound vortex model and trailed vortex model, which is developed based on vortex filament method. By contrast, the far wake model is based on the vortex ring method. This is a good compromise between accuracy and computational cost. In this work, the model is used to assess the influence of floating platform motions on the performance of a horizontal-axis wind turbine rotor. The results are validated on the 5MW NREL rotor and compared with other vortex models for the same rotor subjected to different platform motions. It was found that the result from the proposed method are more reliable than the results from BEM theory especially at small angles of attack in the region of low wind speeds, on the one hand, and high wind speeds with blade pitch motions, on the other hand.

scholarly journals A Modified Free Wake Vortex Ring Method for Horizontal-Axis Wind Turbines

2019 ◽  
Author(s):  
Jing Dong ◽  
Axelle Viré ◽  
Carlos Simao Ferreira ◽  
Zhangrui Li ◽  
Gerard van Bussel
Keyword(s):  
Wind Turbine ◽  
Vortex Ring ◽  
Horizontal Axis ◽  
Wake Vortex ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Vortex Model ◽  
Ring Method ◽  
Wake Model ◽  
Free Wake

A modified free-wake vortex ring model is proposed to compute the dynamics of a floating horizontal-axis wind turbine. The model is divided into two parts. The near wake model uses a blade bound vortex model and trailed vortex model, which is developed based on vortex filament method. By contrast, the far wake model is based on the vortex ring method. The proposed model is a good compromise between accuracy and computational cost, for example when compared with more complex vortex methods. The present model is used to assess the influence of floating platform motions on the performance of a horizontal-axis wind turbine rotor. The results are validated on the 5MW NREL rotor and compared with other aerodynamic models for the same rotor subjected to different platform motions. It was found that the results from the proposed method are more reliable than the results from BEM theory especially at small angles of attack in the region of low wind speeds, on the one hand, and high wind speeds with blade pitch motions, on the other hand. And also the proposed method is less time consuming and has similar accuracy when comparing with more advanced vortex based methods.

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