RANS Computations of MEXICO Rotor in Uniform and Yawed Inflow

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Christina Tsalicoglou ◽  
Samira Jafari ◽  
Ndaona Chokani ◽  
Reza S. Abhari
Keyword(s):  
Wind Turbine ◽  
Wind Farms ◽  
Computational Effort ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Flow Properties ◽  
Horizontal Axis Wind Turbine ◽  
Near Wake ◽  
Measured Flow ◽  
Rans Simulations

Full Reynolds-averaged Navier–Stokes (RANS) simulations of the flow in the near wake of a three-bladed horizontal-axis wind turbine are presented. The simulations, which are based on the model experiments in controlled conditions (MEXICO) experiment and include the complete rotor, nacelle, and tower show good agreement with experimental data, with 4% difference relative to measured flow properties. The flow properties in the near wake are detailed for both uniform and nonuniform flow conditions. The effects of increasing tip-speed ratio and a yawed inflow of 30 deg are studied. The full RANS simulations are used to support the development of an immersed wind turbine model at ETH Zurich. This model allows for modeling of the wake evolution and interactions in wind farms, for multiple turbines, with substantially reduced computational effort.

RANS Computations of Wind Turbine Near-Wake Aerodynamics in Uniform and Yawed Inflow

2013 ◽  
Author(s):  
C. Tsalicoglou ◽  
S. Jafari ◽  
N. Chokani ◽  
R. S. Abhari
Keyword(s):  
Wind Turbine ◽  
Wind Farms ◽  
Computational Effort ◽  
Speed Ratio ◽  
Flow Properties ◽  
Horizontal Axis Wind Turbine ◽  
Near Wake ◽  
Measured Flow ◽  
Rans Simulations ◽  
Good Agreement

Full RANS simulations of the flow in the near wake of a three-bladed horizontal-axis wind turbine are presented. The simulations, which are based on the MEXICO experiment and include the complete rotor, nacelle and tower, show good agreement with experimental data, with 4% difference relative to measured flow properties. The flow properties in the near wake are detailed for both uniform and non-uniform flow conditions. The effects of increasing tip-speed ratio and of yawed inflow of 30° are studied. The full RANS simulations are used to support the development of an immersed wind turbine model at ETH Zurich. This model allows for modeling of the wake evolution and interactions in wind farms, for multiple turbines, with substantially reduced computational effort.

scholarly journals Effect of Wind Tunnel Blockage on the Performance of a Horizontal Axis Wind Turbine with Different Blade Number

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1988 ◽  
Author(s):  
Abdelgalil Eltayesh ◽  
Magdy Bassily Hanna ◽  
Francesco Castellani ◽  
A.S. Huzayyin ◽  
Hesham M. El-Batsh ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Computational Effort ◽  
Horizontal Axis ◽  
Experimental Results ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Small Scale ◽  
Horizontal Axis Wind Turbine ◽  
Cross Section Area

Blockage corrections for the experimental results obtained for a small-scale wind turbine in a wind tunnel are required in order to estimate how the same turbine would perform in real conditions. The tunnel blockage is defined as the ratio of the wind turbine swept area to the wind tunnel cross-section area. Experimental measurements of the power coefficient were performed on a horizontal-axis wind turbine with two rotors of diameter equal to 2 m and different numbers of blades, namely three and five. Measurements were carried out for different tip speed ratios in the closed circuit open test section wind tunnel of the University of Perugia (Italy). The obtained experimental results were compared with the numerical ones carried out in free conditions by using a CFD approach based on the steady-RANS method with the SST k-ω turbulence model, adopting the multiple reference frame (MRF) strategy to reduce the computational effort. The comparison showed that the maximum value of blockage, which is reached in the asymptotic limit at very large tip speed ratio (TSR) values, does not depend appreciably on the number of blades. A higher number of blades, however, makes the occurrence of the maximum blockage come earlier at lower TSRs.

scholarly journals Modeling and simulation of forces applied to the horizontal axis wind turbine rotors by the vortex method coupled with the method of the blade element

2021 ◽  
Vol 12 (1) ◽  
pp. 413
Author(s):  
Ibtissem Barkat ◽  
Abdelouahab Benretem ◽  
Fawaz Massouh ◽  
Issam Meghlaoui ◽  
Ahlem Chebel
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farms ◽  
Vortex Method ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Rotor Blades ◽  
Good Representation ◽  
Horizontal Axis Wind Turbine ◽  
Blade Element

This article aims to study the forces applied to the rotors of horizontal axis wind turbines. The aerodynamics of a turbine are controlled by the flow around the rotor, or estimate of air charges on the rotor blades under various operating conditions and their relation to the structural dynamics of the rotor are critical for design. One of the major challenges in wind turbine aerodynamics is to predict the forces on the blade as various methods, including blade element moment theory (BEM), the approach that is naturally adapted to the simulation of the aerodynamics of wind turbines and the dynamic and models (CFD) that describes with fidelity the flow around the rotor. In our article we proposed a modeling method and a simulation of the forces applied to the horizontal axis wind rotors turbines using the application of the blade elements method to model the rotor and the vortex method of free wake modeling in order to develop a rotor model, which can be used to study wind farms. This model is intended to speed up the calculation, guaranteeing a good representation of the aerodynamic loads exerted by the wind.

Analysis of Unsteady Flows Past Horizontal Axis Wind Turbine Airfoils Based on Harmonic Balance Compressible Navier-Stokes Equations With Low-Speed Preconditioning

2011 ◽  
Author(s):  
M. Sergio Campobasso ◽  
Mohammad H. Baba-Ahmadi
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Harmonic Balance ◽  
Stokes Equations ◽  
Unsteady Aerodynamics ◽  
Horizontal Axis ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed ◽  
Computational Performance

This paper presents the numerical models underlying the implementation of a novel harmonic balance compressible Navier-Stokes solver with low-speed preconditioning for wind turbine unsteady aerodynamics. The numerical integration of the harmonic balance equations is based on a multigrid iteration, and, for the first time, a numerical instability associated with the use of such an explicit approach in this context is discussed and resolved. The harmonic balance solver with low-speed preconditioning is well suited for the analyses of several unsteady periodic low-speed flows, such as those encountered in horizontal axis wind turbines. The computational performance and the accuracy of the technology being developed are assessed by computing the flow field past two sections of a wind turbine blade in yawed wind with both the time- and frequency-domain solvers. Results highlight that the harmonic balance solver can compute these periodic flows more than 10 times faster than its time-domain counterpart, and with an accuracy comparable to that of the time-domain solver.

Navier-Stokes and Comprehensive Analysis Performance Predictions of the NREL Phase VI Experiment

2003 ◽  
Author(s):  
Earl P. N. Duque ◽  
Michael D. Burklund ◽  
Wayne Johnson
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Performance Predictions ◽  
Nasa Ames Research ◽  
Nrel Phase Vi ◽  
Wind Turbine Rotor

A vortex lattice code, CAMRAD II, and a Reynolds-Averaged Navier-Stoke code, OVERFLOW-D2, were used to predict the aerodynamic performance of a two-bladed horizontal axis wind turbine. All computations were compared with experimental data that was collected at the NASA Ames Research Center 80-by 120-Foot Wind Tunnel. Computations were performed for both axial as well as yawed operating conditions. Various stall delay models and dynamics stall models were used by the CAMRAD II code. Comparisons between the experimental data and computed aerodynamic loads show that the OVERFLOW-D2 code can accurately predict the power and spanwise loading of a wind turbine rotor.

Conclusions From the Comparisons of Numerous 2D Airfoil Computations With Experiments

2002 ◽  
Author(s):  
F. Bertagnolio ◽  
N. N. So̸rensen ◽  
J. Johansen ◽  
P. Fuglsang
Keyword(s):  
Wind Turbine ◽  
Numerical Results ◽  
Panel Method ◽  
Navier Stokes ◽  
Flow Properties ◽  
2D Airfoil

The aim of this work is two-fold. Firstly, 28 sets of airfoil (widely used for wind turbine applications) measurements were compared with numerical results from a 2D Navier-Stokes solver and a panel method code. These results have been collected into an airfoil catalogue that has been separately published. Secondly, based on the previous results, criterions for evaluating the airfoils are derived. Thereby, the performance of the Navier-Stokes solver is evaluated. Further analysis of the results determines geometrical and flow properties that may cause problems when computing airfoil flows with a Navier-Stokes solver, and some recommendations are given.

scholarly journals Analysis of Unsteady Flows Past Horizontal Axis Wind Turbine Airfoils Based on Harmonic Balance Compressible Navier-Stokes Equations With Low-Speed Preconditioning

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
M. Sergio Campobasso ◽  
Mohammad H. Baba-Ahmadi
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Harmonic Balance ◽  
Stokes Equations ◽  
Unsteady Aerodynamics ◽  
Horizontal Axis ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed ◽  
Computational Performance

This paper presents the numerical models underlying the implementation of a novel harmonic balance compressible Navier-Stokes solver with low-speed preconditioning for wind turbine unsteady aerodynamics. The numerical integration of the harmonic balance equations is based on a multigrid iteration, and, for the first time, a numerical instability associated with the use of such an explicit approach in this context is discussed and resolved. The harmonic balance solver with low-speed preconditioning is well suited for the analyses of several unsteady periodic low-speed flows, such as those encountered in horizontal axis wind turbines. The computational performance and the accuracy of the technology being developed are assessed by computing the flow field past two sections of a wind turbine blade in yawed wind with both the time-and frequency-domain solvers. Results highlight that the harmonic balance solver can compute these periodic flows more than 10 times faster than its time-domain counterpart, and with an accuracy comparable to that of the time-domain solver.

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