scholarly journals Investigation into Yaw Motion Influence of Horizontal-Axis Wind Turbine on Wake Flow Using LBM-LES

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5248
Author(s):  
Weimin Wu ◽  
Xiongfei Liu ◽  
Jingcheng Liu ◽  
Shunpeng Zeng ◽  
Chuande Zhou ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Aerodynamic Characteristics ◽  
Angular Speed ◽  
Aerodynamic Performance ◽  
Tip Vortex ◽  
Wake Flow ◽  
Horizontal Axis Wind Turbine ◽  
Near Wake ◽  
Eddy Simulation ◽  
Sweep Surface

The dynamic yaw motion of the wind turbine will affect the overall aerodynamic performance of the impeller and the corresponding wake flow, but the current research on this issue is inadequate. Thus, it is very necessary to study the complicated near-wake aerodynamic behaviors during the yaw process and the closely related blade aerodynamic characteristics. This work utilized the multi-relaxation time lattice Boltzmann (MRT-LBM) model to investigate the integral aerodynamic performance characteristics of the specified impeller and the dynamic changes in the near wake under a sine yawing process, in which the normalized result is adopted to facilitate data comparison and understanding. Moreover, considering the complexity of the wake flows, the large eddy simulation (LES) and wall-adapting local eddy-viscosity (WALE) model are also used in this investigation. The related results indicate that the degree of stability of tip spiral wake in the dynamic yaw condition is inversely related to the absolute value of the change rate of yaw angular speed. When the wind turbine returns to the position with the yaw angle of 0 (deg) around, the linearized migration of tip vortex is changed, and the speed loss in the wake center is reduced at about the normalized velocity of 0.27, and another transverse expansion appeared. The directional inducing downstream of the impeller sweep surface for tip vortex is clearly reflected on the entering side and the exiting side. Additionally, the features of the static pressure on the blade surface and the overall aerodynamic effects of the impeller are also discussed, respectively.

PIV Experiment on Near Wake Flow of Horizontal Axis Wind Turbine

2013 ◽  
Vol 718-720 ◽  
pp. 1811-1815 ◽  
Author(s):  
Xiang Gao ◽  
Jun Hu ◽  
Zhi Qiang Wang
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Radial Direction ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Tip Vortex ◽  
Wake Flow ◽  
Horizontal Axis Wind Turbine ◽  
Near Wake ◽  
Piv Measurement

A three-dimensional horizontal axis wind turbine model was experimentally studied. The experiment was carried out in a laboratory wind tunnel. With PIV measurement, details about flow fields in the near wakeof the turbine blade were obtained. The result shows vortices generateon the tailing edge of the blade, and propagatedownstream then dissipate into small vortices. Vortices also generate at the tip of the blade, propagate downstream and along the radial direction then dissipate. The dissipation of the tip vortex is slower than the former. We also find that the wake of turbine blade rotates in the opposite direction of the blade.

Experimental Investigation on the Tip Vortex of a Wind Turbine With and Without a Slotted Tip

2017 ◽  
Author(s):  
Pengyin Liu ◽  
Jinge Chen ◽  
Shen Xin ◽  
Xiaocheng Zhu ◽  
Zhaohui Du
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Wind Turbine ◽  
Vortex Core ◽  
Control Method ◽  
Tip Vortex ◽  
Wake Flow ◽  
Core Model ◽  
Near Wake ◽  
Measured Velocity

In this paper, a slotted tip structure is experimentally analyzed. A wind turbine with three blades, of which the radius is 301.74mm, is investigated by the PIV method. Each wind turbine blade is formed with a slots system comprising four internal tube members embedded in the blade. The inlets of the internal tube member are located at the leading edge of the blade and form an inlet array. The outlets are located at the blade tip face and form an outlet array. The near wake flow field of the wind turbine with slotted tip and without slotted tip are both measured. Velocity field of near wake region and clear images of the tip vortex are captured under different wake ages. The experimental results show that the radius of the tip vortex core is enlarged by the slotted tip at any wake age compared with that of original wind turbine. Moreover, the diffusion process of the tip vortex is accelerated by the slotted tip which lead to the disappearance of the tip vortex occurs at smaller wake age. The strength of the tip vortex is also reduced indicating that the flow field in the near wake of wind turbine is improved. The experimental data are further analyzed with the vortex core model to reveal the flow mechanism of this kind of flow control method. The turbulence coefficient of the vortex core model for wind turbine is obtained from the experimental data of the wind turbine with and without slotted tip. It shows that the slotted tip increases the turbulence strength in the tip vortex core by importing airflow into the tip vortex core during its initial generation stage, which leads to the reduction of the tip vortex strength. Therefore, it is promising that the slotted tip can be used to weaken the vorticity and accelerate the diffusion of the tip vortex which would improve the problem caused by the tip vortex.

Aerodynamic Characteristics of Horizontal Axis Wind Turbine With Archimedes Spiral Blade

2013 ◽  
Author(s):  
Kyung Chun Kim ◽  
Yoon Kee Kim ◽  
Ho Seong Ji ◽  
Jook Ho Beak ◽  
Rinus Mieremet
Keyword(s):  
Steady State ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Aerodynamic Characteristics ◽  
Wake Flow ◽  
Power Coefficient ◽  
Horizontal Axis Wind Turbine ◽  
Mean Velocity ◽  
Archimedes Spiral ◽  
Spiral Blade

To investigate the aerodynamic characteristics of an Archimedes spiral wind turbine for urban-usage, both experimental and numerical studies were carried out. The Archimedes spiral blade was designed to produce wind power using drag and lift forces on the blade together. Instantaneous velocity fields were measured by two-dimensional PIV method in the near field of the blade. Mean velocity profiles were compared to those predicted by the steady state and unsteady state CFD simulation. It was found that the interaction between the wake flow at the rotor downstream and the induced velocity due to the tip vortices were strongly affected by the wind speed and resulting rotational speed of the blade. PIV measurements revealed the presence of dominant vertical structures at downstream the hub and near the blade tip. Unsteady CFD simulation results agreed well with those of PIV experiments than the steady state analysis. The power coefficient (Cp) obtained by CFD simulation demonstrated that the new type of wind turbine produced about 0.25, relatively high value compared to other types of urban-usage wind turbine.

Yawed Effect on Wind Turbine Near Wake

2014 ◽  
Author(s):  
Yuntian Ge ◽  
Xiuling Wang
Keyword(s):  
Wind Turbine ◽  
Flow Pattern ◽  
Wind Turbines ◽  
Air Flow ◽  
Aerodynamic Performance ◽  
Wake Flow ◽  
Near Wake ◽  
Rotation Plane ◽  
The Difference ◽  
Ansys Workbench

Wind turbines rotation was motivated by the force of wind. In reality, wind doesn’t moving vertically to the wind turbine rotation plane, but in random directions instead. Therefore, the yawed effect has to be taken into consideration when study wind turbine aerodynamic performance. The purpose of this study is to compare the difference between the wind turbine near wake flow with yawed effect and without yawed effect aerodynamically. The research uses CFD technology to simulate the rotation movement and air flow pattern, which is completed in software Ansys Workbench.

scholarly journals Effect of Airfoil Concavity on Wind Turbine Blade Performances

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jianlong Ma ◽  
Yafan Duan ◽  
Ming Zhao ◽  
Wenchun Lv ◽  
Jianwen Wang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Aerodynamic Performance ◽  
Pressure Level ◽  
Wind Turbine Blade ◽  
Wake Flow ◽  
Suction Surface ◽  
Horizontal Axis Wind Turbine

Although the optimization of wind turbine blade aerodynamic performance has achieved fruitful results, whether airfoil concavity, an important method for preventing flow separation, is also feasible for improving the aerodynamic performance has not been confirmed scientifically. Thus, we selected the blade of a small horizontal-axis wind turbine as a research model and proposed an optimization method based on airfoil concavity near the trailing edge of the blade suction surface. The experimental results showed that airfoil concavity improved blade aerodynamic performance by 3–15%. Subsequently, its effects on the sound pressure level within the wake flow field were investigated using an acoustic array, and the results suggested that the sound pressure level was reduced by 9.6–15.8%. Lastly, a modal test of the rotor blade was conducted. Although the natural frequencies of the 1st and 2nd order vibrations had hardly changed, their vibrational stiffness were increased by 7 and 4.9%, respectively, which indicated that airfoil concavity significantly improved structural robustness.

Effect of Icing Airfoil on Aerodynamic Performance of Horizontal Axis Wind Turbine

2021 ◽  
pp. 1-9
Author(s):  
Pham Huu Hoang ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
Tetsu Tada ◽  
Hanamura Maito ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Performance Test ◽  
Lift Coefficient ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Axis Wind Turbine ◽  
Turbine Performance ◽  
Maximum Value

Abstract In this paper, the aerodynamic characteristics is clarified by the airfoil performance test of the model of icing airfoil in wind tunnel. As a results of wind tunnel test, the lift coefficient of model of icing airfoil becomes lower and the drag coefficient becomes higher than those of clean airfoil. With the use of these results, numerical analysis using aeroelastic code was carried out to clarify the influence of icing airfoil on wind turbine performance. As result of the analysis, the rated power with icing airfoil is obtained at higher wind speed than clean one, and the maximum value of output power is decreased by icing airfoil. Compared to clean airfoil, the amplitude of edgewise moment at blade root is increased, which is mainly caused by the effects of mass of icing on the blade.

scholarly journals Experimental Investigation of Tip Vortex Meandering in the Near Wake of a Horizontal-Axis Wind Turbine

2017 ◽  
Vol 10 (6) ◽  
pp. 1679-1688 ◽  
Author(s):  
A. W. Dahmouni ◽  
M. M. Oueslati ◽  
S. Ben Nasrallah ◽  
◽  
◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Wind Turbine ◽  
Horizontal Axis ◽  
Tip Vortex ◽  
Horizontal Axis Wind Turbine ◽  
Near Wake

scholarly journals Large-Eddy Simulation of Wind Turbine Flows: A New Evaluation of Actuator Disk Models

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3745
Author(s):  
Tristan Revaz ◽  
Fernando Porté-Agel
Keyword(s):  
Boundary Layer ◽  
Simple Model ◽  
Wind Turbine ◽  
Wake Flow ◽  
Test Case ◽  
Flow Solver ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Layer Flow ◽  
Advanced Model

Large-eddy simulation (LES) with actuator models has become the state-of-the-art numerical tool to study the complex interaction between the atmospheric boundary layer (ABL) and wind turbines. In this paper, a new evaluation of actuator disk models (ADMs) for LES of wind turbine flows is presented. Several details of the implementation of such models are evaluated based on a test case studied experimentally. In contrast to other test cases used in previous similar studies, the present test case consists of a wind turbine immersed in a realistic turbulent boundary-layer flow, for which accurate data for the turbine, the flow, the thrust and the power are available. It is found that the projection of the forces generated by the turbine into the flow solver grid is crucial for rotor predictions, especially for the power, and less important for the wake flow prediction. In this context, the projection of the forces into the flow solver grid should be as accurate as possible, in order to conserve the consistency between the computed axial velocity and the projected axial force. Also, the projection of the force is found to be much more important in the rotor plane directions than in the streamwise direction. It is found that for the case of a wind turbine immersed in a realistic turbulent boundary-layer flow, the potential spurious numerical oscillations originating from sharp force projections are not harmful to the results. By comparing an advanced model which computes the non-uniform distribution of the turbine forces over the rotor with a simple model which assumes uniform effects of the turbine forces, it is found that both can lead to accurate results for the far wake flow and the thrust and power predictions. However, the comparison shows that the advanced model leads to better results for the near wake flow. In addition, it is found that the simple model overestimates the rotor velocity prediction in comparison to the advanced model. These elements are explained by the lack of local feedback between the axial velocity and the axial force in the simple model. By comparing simulations with and without including the effects of the nacelle and tower, it is found that the consideration of the nacelle and tower is relatively important both for the near wake and the power prediction, due to the shadow effects. The grid resolution is not found to be critical once a reasonable resolution is used, i.e. in the order of 10 grid points along each direction across the rotor. The comparison with the experimental data shows that an accurate prediction of the flow, thrust, and power is possible with a very reasonable computational cost. Overall, the results give important guidelines for the implementation of ADMs for LES.

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