scholarly journals The Influence of Tilt Angle on the Aerodynamic Performance of a Wind Turbine

2020 ◽  
Vol 10 (15) ◽  
pp. 5380
Author(s):  
Qiang Wang ◽  
Kangping Liao ◽  
Qingwei Ma
Keyword(s):  
Wind Turbine ◽  
Turbulence Intensity ◽  
Tilt Angle ◽  
Wind Shear ◽  
Cfd Simulation ◽  
Aerodynamic Performance ◽  
Tip Vortices ◽  
Sliding Mesh ◽  
Blade Section ◽  
Lift And Drag

Aerodynamic performance of a wind turbine at different tilt angles was studied based on the commercial CFD software STAR-CCM+. Tilt angles of 0, 4, 8 and 12° were investigated based on uniform wind speed and wind shear. In CFD simulation, the rotating motion of blade was based on a sliding mesh. The thrust, power, lift and drag of the blade section airfoil at different tilt angles have been widely investigated herein. Meanwhile, the tip vortices and velocity profiles at different tilt angles were physically observed. In addition, the influence of the wind shear exponents and the expected value of turbulence intensity on the aerodynamic performance of the wind turbine is also further discussed. The results indicate that the change in tilt angle changes the angle of attack of the airfoil section of the wind turbine blade, which affects the thrust and power of the wind turbine. The aerodynamic performance of the wind turbine is better when the tilt angle is about 4°. Wind shear will cause the thrust and power of the wind turbine to decrease, and the effect of the wind shear exponents on the aerodynamic performance of the wind turbine is significantly greater than the expected effect of the turbulence intensity. The main purpose of the paper was to study the effect of tilt angle on the aerodynamic performance of a fixed wind turbine.

scholarly journals Numerical investigation of stall characteristics for winglet blade of a horizontal axis wind turbine

2021 ◽  
Vol 321 ◽  
pp. 03004
Author(s):  
Shalini Verma ◽  
Akshoy Ranjan Paul ◽  
Anuj Jain ◽  
Firoz Alam
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Numerical Investigation ◽  
Turbulence Intensity ◽  
Geometric Modeling ◽  
Cfd Simulation ◽  
Lift Coefficient ◽  
Horizontal Axis ◽  
Renewable Energy Resources ◽  
Horizontal Axis Wind Turbine

Wind energy is one of the renewable energy resources which is clean and sustainable energy and the wind turbine is used for harnessing energy from the wind. The blades are the key components of a wind turbine to convert wind energy into rotational energy. Recently, wingtip devices are used in the blades of horizontal axis wind turbine (HAWT), which decreases the vortex and drag, while increases the lift and thereby improve the performance of the turbine. In the present study, a winglet is used at the tip of an NREL phase VI wind turbine blade. Solidworks, Pointwise, and Ansys-Fluent are used for geometric modeling, computational grid generation, and CFD simulation, respectively. The computational result obtained using SST k-ω turbulence modeling is well validated with the experimental data of NREL at 5 and 7 m/s of wind speeds. Numerical investigation of stall characteristics is carried out for wingleted blade at higher turbulence intensity (21% and 25%) and angle of attack (00 to 300 at 50 intervals) at 7 m/s wind speed. The result found that wingletd blade delay stall to 150 for both the cases of turbulence intensity. Increasing the turbulence intensity increases the lift coefficient at stall angle but drag coefficient also increases and thus a lower aerodynamic performance (CL/CD ratio = 13) is obtained. Wingleted blade improves the performance as the intensity of vortices is smaller compared to baseline blade

Investigations of Unsteady Aerodynamics of an Offshore Floating Wind Turbine With Platform Motions Using Dual-Sliding Method

2020 ◽  
Author(s):  
Xiaodong Wang ◽  
Zhaoliang Ye ◽  
Ziwen Chen ◽  
Yize Guo ◽  
Yujun Qiao
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Aerodynamic Performance ◽  
Offshore Wind ◽  
Sliding Mesh ◽  
Unsteady Aerodynamic ◽  
Floating Wind Turbine ◽  
Mesh Method ◽  
Offshore Floating Wind Turbine ◽  
Platform Motions

Abstract Offshore wind energy developed rapidly in recent years. Due to the platform motions causing by ocean waves, the aerodynamics of floating offshore wind turbines (FOWT) show strong unsteady characters than onshore wind turbines. The widely used methods to investigate the unsteady aerodynamic performance of wind turbine are Blade Element Momentum (BEM) and Free-Vortex Wake (FVW) methods. The accuracy of these two methods strongly depend on empirical formula or correction models. However, for dynamics motions of wind turbine, there is still a lack of accurate models. CFD simulations using overset or dynamic mesh methods also have been used for FOWT aerodynamic investigations. However, the mesh deforming or reconstruction methods are usually suitable for small movement of wind turbine blade. In this paper, a dual-sliding mesh method is employed to simulate the unsteady aerodynamic characters of an offshore floating wind turbine with supporting platform motions using Unsteady Reynolds Averaged Navier-Stokes (URANS) simulations. Both rotor rotation and platform motions are treated as rigid angular motions. The relative motion and data exchange were simulated using sliding mesh method. The NREL 5MW reference wind turbine with platform pitching and rolling motions are considered. The pitching and rolling motions of floating platform are simplified in the form of a prescribed sinusoidal function. Different conditions with two amplitudes and two frequencies of pitching and rolling motions were investigated. URANS were performed with full structured mesh for wind turbine rotor using commercial software FLUENT. The platform motions were set using User Defined Function (UDF). Transitional Shear Stress Turbulence (T-SST) model was employed. The simulation results were compared with BEM method and FVW method results. Both steady status and dynamic pitching processes are investigated. The variations of wind turbine aerodynamic load, as well as the aerodynamic character of airfoils at different spanwise positions, were obtained and analyzed in detail. The simulations results show that the platform pitching introduce remarkable influence on the wind turbine aerodynamic performance. The platform pitching has much larger influence on the wind turbine power and thrust than the platform rolling. The dual-sliding mesh method shows potentials to investigation the dynamic process with multiple rigid motions.

scholarly journals Aerodynamic Analysis on Wind Turbine Aerofoil

2018 ◽  
Vol 7 (3.27) ◽  
pp. 456
Author(s):  
Albi . ◽  
M Dev Anand ◽  
G M. Joselin Herbert
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Cfd Simulation ◽  
Turbine Blades ◽  
Wind Turbine Blade ◽  
Wind Turbine Blades ◽  
Ansys Fluent ◽  
Wind Speeds ◽  
Drag Forces ◽  
Lift And Drag

The aerofoils of wind turbine blades have crucial influence on aerodynamic efficiency of wind turbine. There are numerous amounts of research being performed on aerofoils of wind turbines. Initially, I have done a brief literature survey on wind turbine aerofoil. This project involves the selection of a suitable aerofoil section for the proposed wind turbine blade. A comprehensive study of the aerofoil behaviour is implemented using 2D modelling. NACA 4412 aerofoil profile is considered for analysis of wind turbine blade. Geometry of this aerofoil is created using GAMBIT and CFD analysis is carried out using ANSYS FLUENT. Lift and Drag forces along with the angle of attack are the important parameters in a wind turbine system. These parameters decide the efficiency of the wind turbine. The lift force and drag force acting on aerofoil were determined with various angles of attacks ranging from 0° to 12° and wind speeds. The coefficient of lift and drag values are calculated for 1×105 Reynolds number. The pressure distributions as well as coefficient of lift to coefficient of drag ratio of this aerofoil were visualized. The CFD simulation results show close agreement with those of the experiments, thus suggesting a reliable alternative to experimental method in determining drag and lift.

Numerical Analysis of a Rooftop Vertical Axis Wind Turbine

2011 ◽  
Author(s):  
N. Cristobal Uzarraga-Rodriguez ◽  
A. Gallegos-Mun˜oz ◽  
J. Manuel Riesco A´vila
Keyword(s):  
Numerical Analysis ◽  
Wind Turbine ◽  
Numerical Study ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Sliding Mesh ◽  
Mesh Model

A numerical analysis of a rooftop vertical axis wind turbine (VAWT) for applications in urban area is presented. The numerical simulations were developed to study the flow field through the turbine rotor to analyze the aerodynamic performance characteristics of the device. Three different blade numbers of wind turbine are studied, 2, 3 and 4, respectively. Each one of the models was built in a 3D computational model. The effects generated in the performance of turbines by the numbers of blades are considered. A Sliding Mesh Model (SMM) capability was used to present the dimensionless form of coefficient power and coefficient moment of the wind turbine as a function of the wind velocity and the rotor rotational speed. The numerical study was developed in CFD using FLUENT®. The results show the aerodynamic performance for each configuration of wind turbine rotor. In the cases of Rooftop rotor the power coefficient increases as the blade number increases, while in the case of Savonius rotor the power coefficient decrease as the blades number increases.

scholarly journals Aerodynamic Performance of a New Double-Flap Wing Sail

2019 ◽  
Vol 26 (4) ◽  
pp. 61-68
Author(s):  
Dongqin Li ◽  
Yili Zhang ◽  
Peng Li ◽  
Jingjing Dai ◽  
Guohuan Li
Keyword(s):  
Cfd Simulation ◽  
Energy Resource ◽  
Weather Conditions ◽  
Aerodynamic Performance ◽  
Natural Energy ◽  
New Type ◽  
Lift And Drag ◽  
Ocean Wind ◽  
Fuel Costs ◽  
Assisted Technologies

Abstract As a type of natural energy resource, wind power is used in the modern implementation of wind-assisted technologies as a method for reducing the fuel consumption and environmental pollution of ocean-going ships. In order to promote the full usage of ocean wind energy for cargo ships, an innovative type of ship propulsion-assisted wing sail is proposed in this paper. The propulsion efficiency of this new wing sail can be increased by enlarging its area in both the transverse and vertical directions in good weather conditions, and it can be folded up automatically in poor weather conditions, improving the sailing safety of the ship. The sail parameters relating to the gaps and rotation angles between different parts of the wing sail are compared, and the values giving the best aerodynamic performance are identified using CFD simulation technology. The results for the lift and drag coefficients for the new wing sail at different attack angles are also compared with those of traditional aerofoil sails, including an arc-shaped rigid sail and a variable-camber sail proposed in 2015. From the viewpoint of the sailing performance of the vessel, our results demonstrate that this new type of wing sail has good aerodynamic performance and can reduce fuel costs for commercial vessels.

scholarly journals 2D CFD Simulation Study on the Performance of Various NACA Airfoils

CFD letters ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 38-50
Author(s):  
Mark Jason Thomas Loutun ◽  
Djamal Hissein Didane ◽  
Mohd Faizal Mohideen Batcha ◽  
Kamil Abdullah ◽  
Mas Fawzi Mohd Ali ◽  
...  
Keyword(s):  
Energy Source ◽  
Wind Turbine ◽  
Computational Models ◽  
Cfd Simulation ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
The Other ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine

The wind is an energy source that has the properties of a clean, free, and readily available energy source. However, the efficiency of the existing rotors used to harness wind power is still not satisfactory. Thus, in this current study, the development and aerodynamic performance investigation of ten NACA airfoils comprising of five symmetrical and five non-symmetrical airfoils have been analyzed through the computational fluids dynamic (CFD) simulation approach. The main motive of this study was to investigate the aerodynamic performance of NACA airfoils to be used on a vertical axis wind turbine (VAWT), which will assist in further understanding the physics of the interaction between airflow and the wind turbine blades. The simulation was performed using two-dimensional computational models based on an unsteady state K-omega Shear Stress Transport (SST) turbulence model. This study covers a parametric study based on the variations of tip-speed ratios and constant wind velocity. The aerodynamic performances are evaluated in terms of torque, torque coefficient, and also power coefficient. The performance of NACA0018 was found to be the best among the other airfoils with a power coefficient of 0.3. NACA0010 displayed the lowest power coefficient among the other airfoils but had a more extensive operating range compared to the other airfoils. However, for non-symmetrical NACA airfoils, NACA2421 scored the highest power coefficient, followed by NACA4412. It was also found that most of the non-symmetrical NACA airfoils can operate at a higher range of tip-speed ratios compared to the symmetrical NACA airfoils.

scholarly journals Performance analysis of a Darrieus-type wind turbine for a series of 4-digit NACA airfoils

2019 ◽  
Author(s):  
Krzysztof Rogowski ◽  
Martin Otto Laver Hansen ◽  
Galih Bangga
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Point Of View ◽  
Navier Stokes ◽  
Vertical Axis Wind Turbine ◽  
Wide Range ◽  
Sst Turbulence Model ◽  
Lift And Drag ◽  
Blade Loads

Abstract. The purpose of this paper is to estimate the H-Darrieus wind turbine aerodynamic performance, aerodynamic blade loads and velocity profiles downstream behind the rotor. The wind turbine model is based on the rotor designed by McDonnell Aircraft Company. The model proposed here consists of three fixed straight blades; in the future this model is planned to be develop with controlled blades. The study was conducted using the unsteady Reynolds averaged Navier-Stokes (URANS) approach with the k-ω shear stress transport (SST) turbulence model. The numerical two-dimensional model was verified using two other independent aerodynamic approaches: the vortex model developed in Technical University of Denmark (DTU) and the extended version of the CFD code FLOWer at the University of Stuttgart (USTUTT). All utilized numerical codes gave similar result of the instantaneous aerodynamic blade loads. In addition, steady-state calculations for the applied airfoils were also made using the same numerical model as for the vertical axis wind turbine (VAWT) to obtain lift and drag coefficients. The obtained values of lift and drag force coefficients, for a Reynolds number of 2.9 million, agree with the predictions of the experiment and XFoil over a wide range of angle of attack. The maximum rotor power coefficients are obtained at 0.5, which makes this impeller attractive from the point of view of further research. This work also addresses the issue of determining the aerodynamic performance of the rotor with various 4-digit NACA airfoils. The effect of two airfoil parameters, maximum airfoil thickness and maximum camber, on aerodynamic rotor performance is investigated. Research has shown that if this rotor were to work with fixed blades it is recommended to use the NACA 1418 airfoil instead of the original NACA 0018.

A Numerical Study of Wind Turbine Airfoil Combined Oscillations Considering Phase Difference under Yaw Loads

2020 ◽  
Author(s):  
Yufeng Yin ◽  
Zhengjie Ji ◽  
Jin Zhang ◽  
Xuan Yin ◽  
Yijie Feng ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Phase Difference ◽  
Numerical Study ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Operating Efficiency ◽  
Wind Turbine Blades ◽  
Pitching Motion ◽  
Blade Section ◽  
Wind Turbine Airfoil

Abstract In order to further improve the operating efficiency of wind turbines and explore the aerodynamic performance of the complex motion of wind turbine blades under yaw loads. In this study, the change in the angle of attack of the blade section airfoil under yaw load can be modeled as an oscillating airfoil and combined with the blade's flapwise motion. The NREL S809 airfoil are chosen for the research, based on the SST k-ω turbulence model with transition correction, under the condition of Reynolds number of 10 6 . The effect of phase difference on its aerodynamic performance under combined flapwise and pitching motion in various flapwise amplitudes and working conditions were analyzed. For the combined oscillations, the effects of the flapwise amplitude ( h ) in the range of 0.2≤ h ≤0.5 are investigated with the phase differences of Φ=±3π/4, ±π/2, ±π/4, 0. The results show that the phase difference between the pitching motion and the flapping motion and the different flapping amplitudes can have a large impact on the aerodynamic performance of the airfoil during dynamic stall, but the degree of influence is greatly different in different situations.

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