Wind Turbine Profile Research Articles

Using Artificial Intelligence to Predict the Aerodynamic Properties of Wind Turbine Profiles

This study describes the use of artificial intelligence to predict the aerodynamic properties of wind turbine profiles. The goal was to determine the lift coefficient for an airfoil using its geometry as input. Calculations based on XFoil were taken as a target for the predictions. The lift coefficient for a single case scenario was set as a value to find by training an algorithm. Airfoil geometry data were collected from the UIUC Airfoil Data Site. Geometries in the coordinate format were converted to PARSEC parameters, which became a direct feature for the random forest regression algorithm. The training dataset included 60% of the base dataset records. The rest of the dataset was used to test the model. Five different datasets were tested. The results calculated for the test part of the base dataset were compared with the actual values of the lift coefficients. The developed prediction model obtained a coefficient of determination ranging from 0.83 to 0.87, which is a good prognosis for further research.

Hybrid axis wind turbine profile design

Wind offers vast opportunities in terms of energy potential. Previous studies have shown that wind power can meet all the world's energy needs by using effective wind turbines. However, the efficiency of wind turbines is not at the expected level, and they are not widely used due to various reasons. In this sense, it is substantial to yield airfoils with better aerodynamic properties. Geometrically, wind turbines are divided into two types as horizontal and vertical axes. Within the scope of this study, it was aimed to design a modified airfoil including both horizontal and vertical axes properties. Accordingly, a hybrid design was made in terms of the airfoil axis obtained by the modification of the NACA4412 profile. In terms of the method of the study, the electric generation efficiency of hybrid airfoils with different inclinations was measured under constant distance and air flow. As a result of the study, it was attained that the modified airfoil curved at an angle of 30° was about 12% more efficient in terms of electricity generation than the unmodified one.

CFD study of active flow control around a wind turbine profile using synthetic jet

In this study, numerical simulations are performed to investigate the effect of the position and jet angle of the synthetic jet on the aerodynamic characteristics of a wind turbine blade profile. The study is applied to the NREL S809 profile with a 1m chord, set at an angle of attack of 15.2° in a flow at a Reynolds number Re=106. The synthetic jet is placed on the extrados of the profile and modeled by a sinusoidal function. The flow around the blade profile is simulated by solving Navier–Stokes equations using the commercial software ANSYS Fluent based on the finite volume method. Turbulence is simulated using the two-equation SST model. The results show that the considered jet parameters have a strong effect on the aerodynamic characteristics of the profile. Applying an optimal combination of synthetic jet parameters significantly improves the aerodynamic performance of the profile.

Computational design & analysis of vertical axis wind turbine

India's energy demand is rising in order to meet the country's current economic development ambitions. The provision of growing amounts of energy is a necessary condition for a country's economic growth. India is heading toward a trend of generating power from renewable resources, owing to the maturity of technological innovations and the pressing need to preserve a healthy environment at a fair cost. Wind energy sector has increased from a fringe activity to a huge multinational business thanks to its safer and environmentally friendly properties. This project aims at utilizing wind energy in an effective approach to get the maximum electric output, which can be implemented in urban areas on the ground, on highways etc. In the present work, vertical axis wind turbine is designed numerically. The blades used are twisted and are connected to the shaft. Analyses are carried out on two vertical axis wind turbine profiles at different wind speeds. Velocity, pressure, and torque characteristics are obtained and compared between the two vertical axis wind turbine models.

Design and static analysis of polymer composite wind turbine blade

Wind power is one of the world's fastest-growing energy sector and relatively mature technologies. Wind power is changing the wind energy into electricity, in which the blade plays a very important role. At present large-scale wind turbine blades are almost made of composite materials. Composite materials are a kind of new materials. Because of its high strength, stiffness, weight-lightness, resistance to fatigue, vibration, high temperature, easy-to-design, etc, the composite laminates plates have been widely used in the wind energy field. Therefore, blade vibration analysis, structural design technology and composite materials technology are closely linked. This is a paper on static analysis of polymer composite material for wind turbine blade. By an analysis using CATIA a better wind turbine profile is to be obtained with increased efficiency of energy generation and reduced damage due to vibration.

Comparison between rare-earth and ferrite permanent magnet flux-switching generators for gearless wind turbines

Flux switching generators with permanent magnets (PMs) on the stator is a good alternative to traditional synchronous generators for gearless wind turbines. This paper is dedicated to the comparison of the 3-phase rare-earth and ferrite PM flux switching generators considered in gearless wind generator application (332 rpm, 1784 W). The machines are designed and optimized using the Nelder–Mead algorithm coupled with 2D FEM model. The objective function is built taking into account the following objectives: the average efficiency of the generators over the wind turbine profile, the required power of the AC–DC converter, the quantity of the magnets and the torque ripple. It is found that the ferrite PM flux switching generator can be an attractive alternative to the rare-earth one. The averaged efficiency of the generator with ferrite PM is higher by 4.1% than that of the rare-earth one. The active power of the ferrite generator is also higher in a wide range of powers. Although the mass of the ferrite PM generator is 2.4 times higher, the costs of the generators are approximately similar since the rare-earth magnets are much more expensive than ferrite ones.

Variation of the Forces with the Wind Direction to an Experimental Model of Aerodynamic Profile of Wind Turbine

Variation of the Forces with the Wind Direction to an Experimental Model of Aerodynamic Profile of Wind Turbine

A Survey on the Potential Flow/Boundary Layer Coupling Methods Applied to Airfoils

Due to the rising demand on renewable energy sources in the last decade, the topic of flow control is getting more attention. In fact, while designing a wind turbine profile, it is necessary to know the location of the separation point on the surface of the profile. So, to design an efficient profile, we have to avoid the flow separation. The aim of this paper is to develop three different computational separation prediction methods to extract the most efficient one of them. The pressure distribution, obtained by the Hess and Smith panel method is used as an input data for each prediction method code. The prediction methods were applied to different wind turbine blade profiles. Comparisons made between our numerical results with experiments show that the integral method is the best method to model the real flow action on the wind turbine profile. Never the less, the integral method was able to correct well the profile aerodynamic coefficients.

Streamwise vortex generator for separation reduction on wind turbine profile

High angles of attack of the wind turbine blades induce severe flow conditions which lead to flow separation and, as the consequence, aerodynamic performance reduction. Implementation of a new type of passive streamwise vortex generator (Rod Vortex Generator - RVG), on a wind turbine profile in order to reduce the flow separation is presented. Numerical model validation is carried out for the S809 aerofoil and a wide range of angles of attack (AoA) employed as reference for flow control cases. Investigation of proposed passive control method involves attached as well as incipient and massive flow separation. A study of chordwise location of RVGs for different inflow conditions is performed. The numerical and experimental results are in good agreement. Obtained numerical results based on the RANS approach reveal a large potential of selected passive devices in reduction of flow separation and increase of aerodynamic performance.

Inverse structure functions in the canonical wind turbine array boundary layer

Wind tunnel measurements for a 3 × 3 canonical wind turbine array boundary layer are obtained using hot-wire anemometer velocity signals. Two downstream locations are considered, referring to the near- and far-wake, and 21 vertical points are acquired per profile. Velocity increments and exit distances are used to quantify inverse structure functions at both downstream locations. Inverse structure functions in the near-wake show a similar profile for the main vertical locations, but diverge as the moment is increased. In the far-wake, inverse structure functions converge toward a single function for all vertical location and moments. The scaling exponents for inverse structure functions are calculated directly and relatively, using extended self similarity. Scaling exponents show strong dependence on vertical position along the wind turbine profile in the near-wake and remain relatively constant in the far-wake. Intermittency in the near-wake is indicated by the nonlinear behavior of the direct and relative scaling exponents when plotted against their respective moments.

Laminar‐turbulent flow simulation for wind turbine profiles using the γ– transition model

ABSTRACTThe accurate prediction of the laminar‐turbulence transition process is fundamental in predicting the aerodynamic performance of wind turbine profiles. Fully turbulent flow simulations have been shown to over‐predict the aerodynamic performance and thereby negatively impacting the design of airfoils in flow regimes where the possible presence of laminar flow could be exploited to improve the performance of wind turbine rotors. Correlation‐based transition modelling offers a fully computational fluid dynamics compatible approach, where the model integrates completely with the existing turbulence model, allows for the prediction of various transition mechanisms, is applicable to three‐dimensional flows and compatible to adjoint‐based design optimization frameworks. The present paper addresses several modifications necessary for a robust transition model and investigates the accuracy of the model for a wide range of angles of attack and Reynolds numbers, which are necessary for a thorough validation of the correlation‐based transition model for wind turbine profiles. The transition model was employed to predict the transition locations; and an assessment of the various transition mechanisms, Reynolds number effects, sectional characteristics and aerodynamic performance for the NLF(1)‐0416 and S809 airfoils is presented with comparisons to experimental data and numerical solutions. Copyright © 2013 John Wiley & Sons, Ltd.

Design of MATLAB/Simulink Modeling of Fixed-pitch Angle Wind Turbine Simulator

This paper presents the model of fixed-pitch angle wind turbine simulator. The purposed dynamic model consists of wind turbine profiles which attribute to the mechanical power and torque characteristics of wind turbine. The objective of this research is to develop and design the fixed-pitch angle wind turbine simulator. The analytical model has been derived representing the wind turbine simulator, to describe the simulation results using a MATLAB/Simulink. The system has been simulated to verify the effectiveness of the fixed-pitch angle wind turbine simulator at over rated rotational speed. The wind turbine simulator can propel an induction generator model. This implies the characteristics of the electrical power. The wind turbine simulator can display mechanical power and torque characteristics following to the wind velocity. The torque from the wind turbine simulator can be used to drive the induction generator to generate the active power fed into the load.

Dynamic stall model for wind turbine airfoils

Abstract A model is presented for aerodynamic lift of wind turbine profiles under dynamic stall. The model combines memory delay effects under attached flow with reduced lift due to flow separation under dynamic stall conditions. The model is based on a backbone curve in the form of the static lift as a function of the angle of attack. The static lift is described by two parameters, the lift at fully attached flow and the degree of attachment. A relationship between these parameters and the static lift is available from a thin plate approximation. Assuming the parameters to be known during static conditions, nonstationary effects are included by three mechanisms: a delay of the lift coefficient of fully attached flow via a second-order filter, a delay of the development of separation represented via a first-order filter, and a lift contribution due to leading edge separation also represented via a first-order filter. The latter is likely to occur during active pitch control of vibrations. It is shown that all included effects can be important when considering wind turbine blades. The proposed model is validated against test data from two load cases, one at fully attached flow conditions and one during dynamic stall conditions. The proposed model is compared with five other dynamic stall models including, among others, the Beddoes–Leishman model and the ONERA model. It is demonstrated that the proposed model performs equally well or even better than more complicated models and that the included nonstationary effects are essential for obtaining satisfactory results. Finally, the influence of camber and thickness distribution on the backbone curve are analysed. It is shown that both of these effects are adequately accounted for via the static input data.