Aerodynamic Performance Investigation under the Influence of Heavy Rain of a NACA 0012 Airfoil for Wind Turbine Applications

2012 ◽  
Vol 6 (6) ◽  
pp. 1228-1235
Author(s):  
Eleni C. Douvi ◽  
Dionissios P. Margaris
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Heavy Rain ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Spherical Particles ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Naca0012 Airfoil ◽  
The Impact

The study of the prediction of the flow field and aerodynamic characteristics of a NACA0012 airfoil in simulated heavy rain, using a computational fluid dynamics code is presented. The simulation of rain is accomplished by using the two-phase flow Discrete Phase Model, which is available in the CFD code. Spherical particles are tracked through the two-dimensional, incompressible air flow field over a NACA0012 airfoil, at a simulated rain rate of 1000 mm/h and operating at Reynolds numbers Re=1×106 and Re=3×106. To validate the CFD developed model, the results are compared with well-established and published experimental data, showing good agreement. The aim of the work was to show the behavior of the airfoil at these conditions and to establish a verified solution method. Lift and drag coefficients are computed at various angles of attack in both dry and wet conditions and the results are compared to show the effects of rain at airfoil performance. The impact of rain on wind turbine performance is also analyzed. It is concluded that rain causes degradation of aerodynamic performance, especially lift is decreased and drag is increased.

scholarly journals Aerodynamic Sensitivity Analysis for a Wind Turbine Airfoil in an Air-Particle Two-Phase Flow

2019 ◽  
Vol 9 (18) ◽  
pp. 3909 ◽  
Author(s):  
Tongqing Guo ◽  
Junjun Jin ◽  
Zhiliang Lu ◽  
Di Zhou ◽  
Tongguang Wang
Keyword(s):  
Wind Turbine ◽  
Stokes Equations ◽  
Angle Of Attack ◽  
Performance Degradation ◽  
Navier Stokes ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Naca0012 Airfoil ◽  
Particle Flows ◽  
Wind Turbine Airfoil

In this paper, the Navier-Stokes equations coupled with a Lagrangian discrete phase model are described to simulate the air-particle flows over the S809 airfoil of the Phase VI blade, the NH6MW25 airfoil of a 6 MW wind turbine blade and the NACA0012 airfoil. The simulation results demonstrate that, in an attached flow, the slight performance degradation is caused by the boundary layer momentum loss. After flow separation, the performance degradation becomes significant and is dominated by a more extensive separation due to particles, since the aerodynamic coefficient increments and the moving distance of separation point present similar variation trends with increasing angle of attack. Unlike the NACA0012 airfoil, a most particle-sensitive angle of attack is found in the light stall region for a wind turbine airfoil, at which the lift decrement and the drag increment reach their peak values. For the S809 airfoil, the most sensitive angle of attack is about 3° higher than that for the maximum lift-to-drag ratio. Hence, the aerodynamic performance of a wind turbine is very susceptible to particles. Based on the most sensitive angles of attack, the more sensitive scope of angles of attack of a blade airfoil and the more sensitive range of rotor tip speed ratios are predicted sequentially. The present study clarifies the principles for the performance degradation of a wind turbine airfoil due to particles and the conclusions are useful for the wind turbine design reducing the particle influences.

Aerodynamic Characteristics of NACA 23015 Landing Configuration with 20o Flap in Simulated Rain

2014 ◽  
Vol 555 ◽  
pp. 108-112
Author(s):  
Shahid Latif ◽  
Zhou Hong ◽  
Muhammad Ismail
Keyword(s):  
Heavy Rain ◽  
Aerodynamic Characteristics ◽  
Continuous Phase ◽  
Phase Flow ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Discrete Phase Modeling ◽  
Wall Film ◽  
Discrete Phase ◽  
Simulated Rain

In our numerical simulation the heavy rain effects have been studied on the aerodynamic performance of 2D cambered NACA 23015 airfoil landing configuration with 20o. We have used preprocessing software gridgen for creation of the landing configuration of the airfoil and then creating mesh around it. Fluent is used to solve the conservation equations. We have used discrete phase modeling (DPM) in Fluent to simulate the rain phenomenon in continuous phase flow by using two phase flow approach. In our study the coupling between the discrete and the continuous phase has been activated. In discrete phase model (DPM), we used the wall film model for the interaction of the continuous and discrete phase. The airfoil landing configuration exhibited significant decrease in lift and increase in drag for a given lift conditions in simulated rain. Post processing software like MATLAB, Tec plot and Origin are used to see the effects of the heavy rain and then results obtained are compared with the experimental results. Our numerical results in most of cases show similar trends with the experiments.

Airfoils Aerodynamic Performance Analysis in Heavy Rain

2012 ◽  
Vol 245 ◽  
pp. 297-302
Author(s):  
Muhammad Ismail ◽  
Yi Hua Cao
Keyword(s):  
Airline Industry ◽  
Heavy Rain ◽  
Quantitative Information ◽  
Aerodynamic Performance ◽  
Small Scale ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Aerodynamic Efficiency ◽  
Discrete Phase ◽  
Cfd Method

Heavy rainfall greatly affects the aerodynamic performance of the aircraft. There are many accidents of aircraft caused by aerodynamic efficiency degradation due to heavy rain. In this paper we have studied the heavy rain effects on the aerodynamic efficiency of NACA 64210 and NACA 0012 airfoils with cruise and landing configuration. For our analysis, CFD method and preprocessing grid generator are used as our main analytical tools, and the simulation of rain is accomplished via two phase flow approach named as Discrete Phase Model (DPM). Raindrops are assumed to be non-interacting, non-deforming, non evaporating and non spinning spheres. Both cruise and landing configurations of airfoils exhibited significant reduction in lift and increase in drag for a given lift condition in simulated rain. Our results are in good agreement with the experimental results. It is expected that the quantitative information gained in this paper will be useful to the operational airline industry and greater effort such as small scale and full scale flight tests should put in this direction to further improve aviation safety.

Numerical Simulation of the Aerodynamic Performance of a H-Type Wind Turbine during Self-Starting

2014 ◽  
Vol 529 ◽  
pp. 296-302 ◽  
Author(s):  
Wei Zuo ◽  
Shun Kang
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Pitch Angle ◽  
Turbulence Modeling ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Time Dependent ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Sst Turbulence Model

The aerodynamic performance and the bypass flow field of a vertical axis wind turbine under self-starting are investigated using CFD simulations in this paper. The influence of pitch angle variations on the performance of the wind turbine during self-starting is presented. A two-dimensional model of the wind turbine with three blades is employed. A commercial software FlowVision is employed in this paper, which uses dynamic Cartesian grid. The SST turbulence model is used for turbulence modeling, which assumes the flow full turbulent. Based on the comparison between the computed time-dependent variations of the rotation speed with the experimental data, the time-dependent variations of the torque are presented. The characteristics of self-starting of the wind turbine are analyzed with the pitch angle of 0o、-2oand 2o. The influence of pitch angle variations on two-dimensional unsteady viscous flow field through velocity contours is discussed in detail.

Prediction of Aerodynamic Noise Radiated From a Vertical-Axis Wind Turbine

2003 ◽  
Author(s):  
Akiyoshi Iida ◽  
Akisato Mizuno ◽  
Kyoji Kamemoto
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Sound Source ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine

Unsteady flow field and flow induced noise of vertical axis wind turbine are numerically investigated. The flow field is numerically calculated by the vortex method with core-spreading model. This simulation obtains aerodynamic performance and aerodynamic forces. Aerodynamic noise is also simulated by using Ffowcs Williams-Hawkings equation with compact body and low-Mach number assumptions. Tip speed of rotor blades are not so high, then the contribution of the moving sound source is smaller than that of the dipole sound source. Since the maximum power coefficient of VAWT can be obtained at lower tip-speed ratio compared to the conventional, horizontal axis wind turbines, the aerodynamic noise from vertical axis wind turbine is smaller than that of the conventional wind turbines at the same aerodynamic performance. This result indicates that the vertical axis wind turbines are useful to develop low-noise wind turbines.

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.

Optimization of NACA 0012 Airfoil Performance in Dynamics Stall Using Continuous Suction Jet

2020 ◽  
Author(s):  
M. Tadjfar ◽  
Siroos Kasmaiee ◽  
S. Noori
Keyword(s):  
Incidence Angle ◽  
Incident Angle ◽  
Active Flow Control ◽  
Optimization Method ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Control Parameters ◽  
Velocity Amplitude ◽  
Naca0012 Airfoil ◽  
Sinusoidal Motion

Abstract Many different active flow control methods are used to manipulate the flow field about aerodynamic surfaces in order to obtain the most desirable aerodynamic performance. Among these techniques, boundary layer suction is one of the most effective techniques used to improve aerodynamic performance of the airfoil. In this study, the configuration of a pure suction jet actuator is optimized over an oscillating NACA0012 airfoil at the Reynolds number of 1.35 × 105 to control the dynamic stall behavior. The airfoil was pitched around the quarter-chord location with a sinusoidal motion and the angle of attack was varied between −5 and 25 degrees. Genetic algorithm was implemented as the optimization method. However, since large number of numerical simulations were required for this purpose, an artificial neural network was employed for training a function between the control parameters and the airfoil aerodynamic coefficients. Aerodynamic performance defined as lift-to-drag ratio was chosen as the objective function of the optimization. Location, velocity amplitude, opening length and jet incidence angle were the control parameters of this optimization. It was shown that when the velocity amplitude and opening length were maximum, the airfoil reached its highest performance. Moreover, the aerodynamic characteristics of the airfoil were remarkably improved when the jet incident angle approached to 90 degrees. Placing the suction jet actuator in the range between 3 to 6 percent of the airfoil chord, was found to have the greatest effect on improving the aerodynamic performance. For the optimum configuration, the airfoil separation. It was shown that when the velocity amplitude and opening length were maximum, the airfoil reached its highest performance. Moreover, the aerodynamic characteristics of the airfoil were peaked in the range between 90 to 120 degrees, with 107 having the best performance in our database.

scholarly journals Numerical Simulation of Gas-Particle Two-Phase Flow in a Nozzle with DG Method

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Duan Maochang ◽  
Yu Xijun ◽  
Chen Dawei ◽  
Qing Fang ◽  
Zou Shijun
Keyword(s):  
Flow Field ◽  
Gas Phase ◽  
Mass Fraction ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Dg Method ◽  
The Impact

In this paper, the discontinuous Galerkin (DG) method is applied to solve the governing equations of the dispersed two-phase flow with the two-fluid Euler/Euler approach. The resulting governing equations are simple in form and the solution process is very natural. The characteristics of the gas-particle two-phase flow in an engine nozzle are mainly analyzed, and the impacts of the particle mass fraction and particle size on the flow field and engine performance are evaluated. Because of the addition of particles, the gas flow field undergoes significant modifications. Increase in the mass fraction leads to a significant thrust loss in the gas phase, and the impact of the particles on the gas phase could be substantial. Therefore, a quantitative study of thrust loss in the nozzle due to the particle impact is made. It is found that the gas thrust in the two-phase flow is reduced, but the total thrust of the two-phase flow increases to a certain extent.

Optimized Shroud Design for Axial Turbine Aerodynamic Performance

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
L. Porreca ◽  
A. I. Kalfas ◽  
R. S. Abhari
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Field Analysis ◽  
Test Cases ◽  
Axial Turbine ◽  
Significant Difference ◽  
Flow Field Analysis ◽  
The Impact ◽  
Partial Shroud

This paper presents a comprehensive study of the effect of shroud design in axial turbine aerodynamics. Experimental measurements and numerical simulations have been conducted on three different test cases with identical blade geometry and tip clearances but different shroud designs. The first and second test cases are representative of a full shroud and a nonaxisymmetric partial shroud geometry while the third test case uses an optimized partial shroud. Partial shrouds are sometimes used in industrial application in order to benefit from the advantage of shrouded configuration, as well as reduce mechanical stress on the blades. However, the optimal compromise between mechanical considerations and aerodynamic performances is still an open issue due to the resulting highly three-dimensional unsteady flow field. Aerodynamic performance is measured in a low-speed axial turbine facility and shows that there are clear differences between the test cases. In addition, steady and time resolved measurements are performed together with computational analysis in order to improve the understanding of the effect of the shroud geometry on the flow field and to quantify the sources of the resultant additional losses. The flow field analysis shows that the effect of the shroud geometry is significant from 60% blade height span to the tip. Tip leakage vortex in the first rotor is originated in the partial shroud test cases while the full shroud case presents only a weak indigenous tip passage vortex. This results in a significant difference in the secondary flow development in the following second stator with associated losses that varies by about 1% in this row. The analysis shows that the modified partial shroud design has improved considerably the aerodynamic efficiency by about 0.6% by keeping almost unchanged the overall weight of this component, and thus blade root stresses. The work, therefore, presents a comprehensive flow field analysis and shows the impact of the shroud geometry in the aerodynamic performance.

Numerical Study of Effects of AJVG on Aerodynamic Performance and Speed Control of Small-Scale Fixed-Pitch HAWT

2014 ◽  
Author(s):  
Xiang Gao ◽  
Jun Hu ◽  
Zhiqiang Wang ◽  
Chenkai Zhang
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Output Power ◽  
Vortex Generator ◽  
Speed Control ◽  
Aerodynamic Performance ◽  
Small Scale ◽  
Air Jet ◽  
Blade Tip ◽  
Fixed Pitch

Due to the feature of structure simplicity, lower production cost and maintenance ease, fixed pitch variable speed wind turbine has been widely used in non-grid-connected wind power systems. The calculation of wind turbine performance plays an important part in the design of wind turbines. Aerodynamic performance calculation is particularly significant in the fixed pitch stall-regulated wind turbine aerodynamic design process. To enhance the output power and power coefficient of wind turbine, active flow control technologies such as vortex generator are adopted in recent years. In this paper, a small wind turbine with air jet vortex generator (AJVG) on the blade tip is designed, and the output power of the wind turbine gets changed by operating the air jet. Computational Fluid Dynamics method is chosen to obtain aerodynamic characteristics of the wind turbine with/without AJVG and these features are furtherly integrated with speed control method to get speed control strategy under full-speed circumstance. It can be found after complete comparison that through setting AJVG at the blade tip, the new speed control features can help make it operate more stably in a wide range of wind speed without changing the existing wind turbine blades profiles and pitch angle. Also details of the flow field are obtained when solving the three-dimensional Navier-Stokes Equations. By analyzing the flow field of wind turbine with/without AJVG, the influence mechanism of the AJVG is demonstrated in this paper.

Sign in / Sign up

Export Citation Format

Share Document