scholarly journals Propagation of Shock on NREL Phase VI Wind Turbine Airfoil under Compressible Flow

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Mohammad A. Hossain ◽  
Ziaul Huque ◽  
Raghava R. Kammalapati
Keyword(s):  
Shock Waves ◽  
Wind Turbine ◽  
Compressible Flow ◽  
Turbulent Viscosity ◽  
Pressure Coefficient ◽  
Angle Of Attack ◽  
Extreme Condition ◽  
Bottom Surface ◽  
Shock Propagation ◽  
Nrel Phase Vi

The work is focused on numeric analysis of compressible flow around National Renewable Energy Laboratory (NREL) phase VI wind turbine blade airfoil S809. Although wind turbine airfoils are low Reynolds number airfoils, a reasonable investigation of compressible flow under extreme condition might be helpful. A subsonic flow (mach no.M=0.8) has been considered for this analysis and the impacts of this flow under seven different angles of attack have been determined. The results show that shock takes place just after the mid span at the top surface and just before the mid span at the bottom surface at zero angle of attack. Slowly the shock waves translate their positions as angle of attack increases. A relative translation of the shock waves in upper and lower face of the airfoil are presented. Variation of Turbulent viscosity ratio and surface Y+ have also been determined. Ak-ωSST turbulent model is considered and the commercial CFD code ANSYS FLUENT is used to find the pressure coefficient (Cp) as well as the lift (CL) and drag coefficients (CD). A graphical comparison of shock propagation has been shown with different angle of attack. Flow separation and stream function are also determined.

Dynamic Stall on Rotating Airfoils: A Look at the N-Sequence Data from the NREL Phase VI Experiment

2013 ◽  
Vol 569-570 ◽  
pp. 611-619 ◽  
Author(s):  
Srinivas Guntur ◽  
Niels N. Sørensen ◽  
Scott Schreck
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Sequence Data ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Dynamic Stall ◽  
Wind Turbine Blades ◽  
Flow Solver ◽  
The Mean ◽  
Nrel Phase Vi

This paper presents an investigation on the combined effect of dynamic stall and rotational augmentation on wind turbine blades. Dynamic stall and rotational augmentation have previously been studied independently. The NREL Phase VI experiment was one large scale experiment that recorded 3D measurements on rotating and pitching airfoils, and using some these data the behaviour of the unsteady CL-α polars under the influence of rotation is investigated. Unsteady DES CFD computations of the Phase VI rotor in axial operation and continuous pitching conditions (reproducing conditions similar to the N-sequence experiments) for select cases have also been carried out using the in-house flow solver EllipSys3D. The resulting set of CL-α curves for the airfoils in rotation operating at various values of the frequency, the mean, and the amplitude of the angle of attack resulting from the CFD computations as well as those from the experiments are presented and discussed. Qualitative differences between dynamic stall occurrence on rotating and stationary airfoils are highlighted, procedures employed to extract the mean angle of attack from the available experimental data are discussed, and comments are made on the application of dynamic stall models in conjunction with 3D augmentation models on the rotating wind turbine blades.

A New Method for Horizontal Axis Wind Turbine Angle of Attack Determination

2013 ◽  
Vol 291-294 ◽  
pp. 425-428 ◽  
Author(s):  
Mohammad Moshfeghi ◽  
Kun Lu ◽  
Yong Hui Xie
Keyword(s):  
Wind Turbine ◽  
High Velocity ◽  
Normal Force ◽  
Data Extraction ◽  
Angle Of Attack ◽  
Horizontal Axis ◽  
New Method ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Nrel Phase Vi

This paper proposes a new method for horizontal axis wind turbine (HAWT) angle of attack (AOA) determination. Despite common circular planes for data extraction, here, data is extracted on rectangular planes. NREL Phase VI is used for validation of the method. Results show that even in a high velocity wind the proposed plane can be an appropriate choice. Furthermore, the average radial distributions of axial and tangential induction factors are calculated based on the velocity values at the planes. Moreover, local normal force coefficients are calculated and then, the local AOA are compared with 2D results and other 3D values for different wind speeds.

scholarly journals Corrigendum to “Propagation of Shock on NREL Phase VI Wind Turbine Airfoil under Compressible Flow”

2016 ◽  
Vol 2016 ◽  
pp. 1-1
Author(s):  
Mohammad A. Hossain ◽  
Ziaul Huque ◽  
Raghava R. Kommalapati
Keyword(s):  
Wind Turbine ◽  
Compressible Flow ◽  
Wind Turbine Airfoil ◽  
Nrel Phase Vi

NREL Phase VI Wind Turbine Modeling Using an Unsteady Panel Method

2014 ◽  
Author(s):  
Eugene Grigoriev ◽  
Iman Borazjani
Keyword(s):  
Wind Turbine ◽  
Pressure Coefficient ◽  
Pressure Profile ◽  
Panel Method ◽  
Rate Of Change ◽  
Inviscid Flows ◽  
Thrust Coefficient ◽  
Pitching Motion ◽  
Unsteady Panel Method ◽  
Nrel Phase Vi

Wind energy production has been increasing steadily in the past decade. The majority of wind power is generated by horizontal axis wind turbines (HAWT). We investigate the modeling of the HAWT using the vortex panel method, which is an inviscid, steady, computationally inexpensive method. Pressure coefficient profiles, calculated by the vortex panel method, were compared to NREL phase VI wind turbine experiments under two different flow conditions. We show that if the flow is not separated over the blade, the vortex panel method can capture the pressure profile on the blade. Furthermore, the panel method has been extended to handle unsteady inviscid flows to investigate the effect of blade oscillations on the power generation, which is not known. The unsteady behavior is modeled by accounting for the time rate of change of circulation. Unsteady effects due to heaving and pitching motion were quantified for different blade oscillation frequencies. It is estimated that the mean thrust coefficient with heaving and pitching motion can be higher than the thrust generated without blade motion in some cases assuming that the flow does not separate.

Evaluation of the influence of wind speed and angle of attack on the aerodynamic effect of wind turbine blades

2017 ◽  
Author(s):  
Salete Alves ◽  
Luiz Guilherme Vieira Meira de Souza ◽  
Edália Azevedo de Faria ◽  
Maria Thereza dos Santos Silva ◽  
Ranaildo Silva
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Wind Turbine Blades ◽  
Aerodynamic Effect

Three-Dimensional and Rotational Aerodynamics on the NREL Phase VI Wind Turbine Blade

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alvaro Gonzalez ◽  
Xabier Munduate
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Separated Flow ◽  
Leading Edge ◽  
Wind Turbine Blade ◽  
Trailing Edge ◽  
Rotating Blade ◽  
Nrel Phase Vi ◽  
Edge Separation

This work undertakes an aerodynamic analysis over the parked and the rotating NREL Phase VI wind turbine blade. The experimental sequences from NASA Ames wind tunnel selected for this study respond to the parked blade and the rotating configuration, both for the upwind, two-bladed wind turbine operating at nonyawed conditions. The objective is to bring some light into the nature of the flow field and especially the type of stall behavior observed when 2D aerofoil steady measurements are compared to the parked blade and the latter to the rotating one. From averaged pressure coefficients together with their standard deviation values, trailing and leading edge separated flow regions have been found, with the limitations of the repeatability of the flow encountered on the blade. Results for the parked blade show the progressive delay from tip to root of the trailing edge separation process, with respect to the 2D profile, and also reveal a local region of leading edge separated flow or bubble at the inner, 30% and 47% of the blade. For the rotating blade, results at inboard 30% and 47% stations show a dramatic suppression of the trailing edge separation, and the development of a leading edge separation structure connected with the extra lift.

Performance Enhancement Analysis of a Horizontal Axis Wind Turbine by Vortex Trapping Cavity

2021 ◽  
pp. 1-13
Author(s):  
Khaoula Qaissi ◽  
Omer A Elsayed ◽  
Mustapha Faqir ◽  
Elhachmi Essadiqi
Keyword(s):  
Wind Turbine ◽  
Performance Enhancement ◽  
Lift Coefficient ◽  
Separated Flow ◽  
National Renewable Energy Laboratory ◽  
Wake Region ◽  
High Twist ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Nrel Phase Vi

Abstract A wind turbine blade has the particularity of containing twisted and tapered thick airfoils. The challenge with this configuration is the highly separated flow in the region of high twist. This research presents a numerical investigation of the effectiveness of a Vortex Trapping Cavity (VTC) on the aerodynamics of the National renewable Energy laboratory (NREL) Phase VI wind turbine. First, simulations are conducted on the S809 profile to study the fluid flow compared to the airfoil with the redesigned VTC. Secondly, the blade is simulated with and without VTC to assess its effect on the torque and the flow patterns. The results show that for high angles of incidence at Rec=106, the lift coefficient increases by 10% and the wake region appears smaller for the case with VTC. For wind speeds larger than 10 m/s, the VTC improves the torque by 3.9%. This is due to the separation that takes place in the vicinity of the VTC and leads to trapping early separation eddies inside the cell. These eddies roll up forming a coherent laminar vortex structure, which in turn sheds periodically out of the cell. This phenomenon favourably reshapes excessive flow separation, reenergizes the boundary layer and globally improves blade torque.

Development of the Third Darrieus Blade of Sultan Wind Turbine for Low Wind Speed

2015 ◽  
Vol 758 ◽  
pp. 13-19 ◽  
Author(s):  
Erwin ◽  
Slamet Wiyono ◽  
Erny Listijorini ◽  
Rina Lusiani ◽  
Tresna P. Soemardi
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Angle Of Attack ◽  
Optimum Combination ◽  
Chord Length ◽  
The Third ◽  
Low Wind Speed ◽  
A Value ◽  
Power Turbine ◽  
Naca 0012

Use of NACA 0012 at the Sultan Wind Turbine prototype provide value coefficient power turbine at wind speed 5.5 m / s by 0017 , wind speed 6.1 m / s at 0.015 , wind speed 7.7 m / s at 0.016 , wind speed 6.5 m / s for 0018 and wind speed 6.2 m / s by 0017 . Where the value of the highest efficiency obtained at a speed of 6.5 m / s at 0.018 . This result is not as expected to generate sufficient energy.The next development carried out investigations on some kind of airfoil, from investigations obtained by using Qblade software that NACA 6612 has a value of 1.78 CL at 15 degrees angle of attack is the largest of all the airfoil .In this research, NACA 6612 will be simulated with a variable chord length, angle of attack, and wind speed, of these three variables will be created which will map graphics 3d sliding value of the ratio of the 3 variables, this graph will give recommendations most optimum combination of variables to types are mapped wind speed throughout the year, to produce optimum power.Optimum combination of NACA 6612 with wind speed varied from 2-7 m/s is chord length 30 cm and angle of attack 7 degree.

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