scholarly journals Computational Aerodynamic Analysis of Offshore Upwind and Downwind Turbines

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Qiuying Zhao ◽  
Chunhua Sheng ◽  
Abdollah Afjeh
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Computational Analysis ◽  
Bending Moment ◽  
Horizontal Axis ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Horizontal Axis Wind Turbines ◽  
Computational Fluid Dynamics Cfd ◽  
Insight Into

Aerodynamic interactions of the model NREL 5 MW offshore horizontal axis wind turbines (HAWT) are investigated using a high-fidelity computational fluid dynamics (CFD) analysis. Four wind turbine configurations are considered; three-bladed upwind and downwind and two-bladed upwind and downwind configurations, which operate at two different rotor speeds of 12.1 and 16 RPM. In the present study, both steady and unsteady aerodynamic loads, such as the rotor torque, blade hub bending moment, and base the tower bending moment of the tower, are evaluated in detail to provide overall assessment of different wind turbine configurations. Aerodynamic interactions between the rotor and tower are analyzed, including the rotor wake development downstream. The computational analysis provides insight into aerodynamic performance of the upwind and downwind, two- and three-bladed horizontal axis wind turbines.

Fast CFD Simulation of Horizontal Axis Wind Turbines

2010 ◽  
Author(s):  
Fabio De Bellis ◽  
Luciano A. Catalano ◽  
Andrea Dadone
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Cfd Simulation ◽  
Flow Distribution ◽  
Horizontal Axis ◽  
Wall Functions ◽  
Mesh Topology ◽  
Numerical Predictions ◽  
Horizontal Axis Wind Turbines ◽  
Time Required

The numerical simulation of horizontal axis wind turbines (HAWT) has been analysed using computational fluid dynamics (CFD) with the aim of obtaining reliable but at the same time affordable wind turbine simulations, while significantly reducing required overall resources (time, computational power, user skills), for example in an optimization perspective. Starting from mesh generation, time required to extract preliminary aerodynamic predictions of a wind turbine blade has been shortened by means of some simplifications, i.e.: fully unstructured mesh topology, reduced grid size, incompressible flow assumption, use of wall functions, commercial available CFD package employment. Ansys Fluent software package has been employed to solve Reynolds Averaged Navier Stokes (RANS) equations, and results obtained have been compared against NREL Phase VI campaign data. The whole CFD process (pre-processing, processing, postprocessing) has been analysed and the chosen final settings are the result of a trade-off between numerical accuracy and required resources. Besides the introduced simplifications, numerical predictions of shaft torque, forces and flow distribution are in good agreement with experimental data and as accurate as those calcuted by other more sophisticated works.

Development and Application of a Simulation Tool for Vertical and Horizontal Axis Wind Turbines

2013 ◽  
Author(s):  
David Marten ◽  
Juliane Wendler ◽  
Georgios Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Horizontal Axis ◽  
Vertical Axis Wind Turbine ◽  
First Case ◽  
Horizontal Axis Wind Turbines ◽  
Lift And Drag ◽  
The Impact

A double-multiple-streamtube vertical axis wind turbine simulation and design module has been integrated within the open-source wind turbine simulator QBlade. QBlade also contains the XFOIL airfoil analysis functionalities, which makes the software a single tool that comprises all functionality needed for the design and simulation of vertical or horizontal axis wind turbines. The functionality includes two dimensional airfoil design and analysis, lift and drag polar extrapolation, rotor blade design and wind turbine performance simulation. The QBlade software also inherits a generator module, pitch and rotational speed controllers, geometry export functionality and the simulation of rotor characteristics maps. Besides that, QBlade serves as a tool to compare different blade designs and their performance and to thoroughly investigate the distribution of all relevant variables along the rotor in an included post processor. The benefits of this code will be illustrated with two different case studies. The first case deals with the effect of stall delaying vortex generators on a vertical axis wind turbine rotor. The second case outlines the impact of helical blades and blade number on the time varying loads of a vertical axis wind turbine.

scholarly journals Modified Design of Savonius Wind Turbine Blade for Performance Improvement

2019 ◽  
Vol 9 (1) ◽  
pp. 1432-1437
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
New Technologies ◽  
Vertical Axis ◽  
Horizontal Axis ◽  
Wind Speeds ◽  
Wind Potential ◽  
Horizontal Axis Wind Turbines ◽  
Savonius Wind Turbine ◽  
Low Performance

In the context of worldwide energetic transition, wind energy shows up as one of the most prominent renewable energy to provide an alternative for the conventional energy source. Therefore, new technologies of a wind turbine are developed, horizontal axis wind turbines have been extensively investigated and evolved. However, the development of vertical axis wind turbines is still an open and area of research, The main objective is to develop a more efficient type of wind turbines able to operate at low wind speeds to take hold maximum wind potential, The Savonius rotor goes with such conditions, however, it faces critical drawbacks, in particular, the low performance in comparison with horizontal axis wind turbines, as well, the blade in return of savonius wind turbine generates a negative torque leading to a decrement of turbine performance. The present work aims to investigate a modified model of the conventional Savonius rotors with a focus on improving the coefficient of power, transient computational fluid dynamics (CFD) simulations are carried out in an effort to perform a validation of numerical results according to experimental data, also to conduct a comparative analysis of both savonius models

Analysis on Aerodynamic Performance of Horizontal Axis Wind Turbine Based on Nonlinear Wake Model

2013 ◽  
Vol 448-453 ◽  
pp. 1716-1720
Author(s):  
Rui Yang ◽  
Jiu Xin Wang ◽  
Sheng Long Zhang
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Optimization Design ◽  
Aerodynamic Performance ◽  
Horizontal Axis ◽  
Wake Vortex ◽  
Horizontal Axis Wind Turbine ◽  
Horizontal Axis Wind Turbines ◽  
Wake Model ◽  
Induced Velocity

A computational method based on nonlinear wake model was established for horizontal axis wind turbines aerodynamic performance prediction. This method makes use of finite difference method to solve the integral differential equation of the model, the induced velocity of wake vortex can be calculated from equations and compared with the induced velocity of wake vortex in linear model. The comparison between the calculated results of wind turbine under axis flow condition, including tip vortex geometry and aerodynamic performance, and available experimental data shows that this method is suitable for wind turbine aerodynamic performance analysis. Finally, a series of numerical calculations were made to investigate the change of wake geometry and aerodynamic performance of the wind turbine when yawing and pitch angle increasing, which provide foundations for aerodynamic optimization design of horizontal axis wind turbines.

scholarly journals Observation of the Starting and Low Speed Behavior of Small Horizontal Axis Wind Turbine

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Sikandar Khan ◽  
Kamran Shah ◽  
Izhar-Ul-Haq ◽  
Hamid Khan ◽  
Sajid Ali ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Starting Time ◽  
Speed Range ◽  
Horizontal Axis Wind Turbines ◽  
Starting Torque ◽  
High Angles Of Attack

This paper describes the starting behavior of small horizontal axis wind turbines at high angles of attack and low Reynolds number. The unfavorable relative wind direction during the starting time leads to low starting torque and more idling time. Wind turbine models of sizes less than 5 meters were simulated at wind speed range of 2 m/s to 5 m/s. Wind turbines were modeled in Pro/E and based on the optimized designs given by MATLAB codes. Wind turbine models were simulated in ADAMS for improving the starting behavior. The models with high starting torques and less idling times were selected. The starting behavior was successfully improved and the optimized wind turbine models were able to produce more starting torque even at wind speeds less than 5 m/s.

Validation of a Dynamic Prescribed Vortex Wake Model for Horizontal Axis Wind Turbines

2007 ◽  
Author(s):  
Hugh D. Currin ◽  
Frank N. Coton
Keyword(s):  
Structural Dynamics ◽  
Wind Turbines ◽  
Horizontal Axis ◽  
Vortex Wake ◽  
Dynamic Flow ◽  
Unsteady Aerodynamic ◽  
Horizontal Axis Wind Turbines ◽  
Aerodynamic Experiment ◽  
Wake Model

A new aerodynamic wake model for Horizontal Axis Wind Turbines has been developed. The prescribed vortex wake code HAWTDAWG has been extended to dynamic flow and incorporated into AeroDyn. Linkage to the FAST structural dynamics code is retained. Static and dynamic yawed flow validation is done against Unsteady Aerodynamic Experiment Phase VI data as well as against existing code results.

scholarly journals Establishing a robust testing approach for displacement measurement on a rotating horizontal-axis wind turbine

2018 ◽  
Vol 3 (1) ◽  
pp. 301-311
Author(s):  
Nadia Najafi ◽  
Allan Vesth
Keyword(s):  
Wind Turbine ◽  
Camera Calibration ◽  
Wind Turbines ◽  
Calibration Method ◽  
Horizontal Axis ◽  
Tracking Algorithm ◽  
Displacement Measurement ◽  
Horizontal Axis Wind Turbine ◽  
Damage And Failure ◽  
Horizontal Axis Wind Turbines

Abstract. Health monitoring by conventional sensors like accelerometers or strain gauges becomes challenging for large rotating structures due to the issues with feasibility, sensing and data transmission. In addition, acceleration measurements have low capability of presenting very small frequencies, which happen very often for large structures (for instance, frequencies between 0.2 and 0.5 Hz in horizontal-axis wind turbines). By contrast, displacement measurement using stereo vision is rapid, non-contacting and distributed over the structure. The sensors are cheaper and more easily applied to many places on the object to be measured. Horizontal-axis wind turbines are one of the most important large rotating structures and need to be measured and monitored in time to prevent damage and failure, and the blade tip position is one of the key parameters to measure in order to prevent the blade hitting the turbine tower. This paper presents a clearly described and easily applicable procedure for measuring the displacement on the components of a rotating horizontal-axis wind turbine with stereophotogrammetry. Paper markers have been applied on the rotor and tower of a scaled-down horizontal-axis wind turbine model in the workshop and the displacement measurement method has been demonstrated by measuring displacement during operation. The method is mainly developed in two parts: (1) camera calibration and (2) tracking algorithm. We introduce an efficient camera calibration method for measurement in large fields of view, which has always been a challenge. This method is easy and practical and offers better accuracy compared with 2-D traditional camera calibration. The tracking algorithm also works successfully and is able to track the points during rotation within the measurement time. Finally, the accuracy analysis has been conducted and has shown better accuracy of the new calibration method compared with 2-D traditional camera calibration.

scholarly journals Investigation of Turbulence Model Performance in Computational Fluid Dynamics Simulations of Horizontal Axis Wind Turbines

2020 ◽  
Author(s):  
Keaton Mullenix ◽  
D. Keith Walters ◽  
Arturo Villegas ◽  
F. Javier Diez
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Renewable Energy Sources ◽  
Critical Role ◽  
The United States ◽  
Horizontal Axis ◽  
Small Scale ◽  
Horizontal Axis Wind Turbines

Abstract Wind turbines are critically important in the quest to decrease global dependence on non-renewable energy sources. With the space to add 5M wind turbines, the United States is at the forefront of this transition. Horizontal axis wind turbines (HAWTs) have been studied numerically and experimentally at length. The vast majority of computational fluid dynamics (CFD) studies of HAWTs documented in the open literature have been carried out using two-dimensional simulations. Currently, the available three-dimensional simulations do not provide a comprehensive investigation of the accuracy of different options for modeling of fluid turbulence. In this paper four sets of CFD simulations are carried out using four different turbulence models that are commonly used for engineering level CFD analysis: SST-k-ω, Transition k-kL-ω, Standard k-ε, and Monotonically Integrated Large Eddy Simulation (MILES). These models were compared with experimental performance and coefficient of power results for a small-scale industrial wind turbine with inverse tip speed ratios (λ−1) in the range 0.072–0.144. They were further investigated to highlight the similarities and differences for the prediction of coefficient of pressure and skin friction coefficient. The results showed that no singular model, of the four investigated, was able to consistently predict the power performance with a high degree of accuracy when compared to the experimental results. The models also exhibited both similarities and key differences for the other aspects of flow physics. The results presented in this study highlight the critical role that turbulence modeling plays in the overall accuracy of a CFD simulation, and indicate that end users should be well aware of the uncertainties that arise in CFD results for wind turbine analysis, even when other sources of numerical error have been carefully minimized.

Performance Enhancement of Horizontal Axis Wind Turbine Using Numerical Techniques

2021 ◽  
Author(s):  
Poornima Menon ◽  
Srinivas G
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Performance Enhancement ◽  
Horizontal Axis ◽  
Horizontal Wind ◽  
Horizontal Axis Wind Turbine ◽  
Ansys Fluent ◽  
Horizontal Axis Wind Turbines ◽  
Design Requirements ◽  
Nrel Phase Vi

Abstract Wind turbines are one of the most prominent and popular sources of renewable energy, of which, horizontal axis wind turbines (HAWT) are the majorly chosen design for wind machines. These turbines rotate about the horizontal axis which is parallel to the ground. They comprise of aerodynamic blades (generated from the desired airfoil), that may be twisted or tapered as per the design requirements. The blades are attached to a rotor which is located either upwind or downwind. To help wind the orientation of the turbines, the upwind rotors have a tail vane, while the downwind rotors are coned which in turn help them to self-orient. One of the major reasons for the popularity of the horizontal wind turbine, is its ability to generate a larger amount of electricity for a given amount of wind. Due to its popularity, the enhancement in the design of HAWTs, is a major focus area for research. In the present study, a scaled-down CFD model of the NREL Phase VI was validated against the numerical and experimental data. The model used had a dual blade rotor and applied the S809 airfoil. The simulations were carried out using a rotating mesh in ANSYS Fluent. Validation was carried out for 3 velocities — 7m/s, 10m/s and 20m/s. Once validation was carried out, turbine was modified with the addition of vortex generators, in the form of cylindrical protrusions that reduce flow separation.

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