scholarly journals CFD Analysis and Shape Optimization of Airfoils Using Class Shape Transformation and Genetic Algorithm—Part I

2021 ◽  
Vol 11 (9) ◽  
pp. 3791
Author(s):  
Md Tausif Akram ◽  
Man-Hoe Kim
Keyword(s):  
Genetic Algorithm ◽  
Shape Optimization ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Phase Iii ◽  
Cfd Analysis ◽  
Shape Transformation ◽  
Stability Parameters ◽  
Drag Ratio ◽  
Lift To Drag Ratio

This paper presents the parameterization and optimization of two well-known airfoils. The aerodynamic shape optimization investigation includes the subsonic (NREL S-821) and transonic airfoils (RAE-2822). The class shape transformation is employed for parametrization while the genetic algorithm is used for optimization purposes. The absolute scheme of the optimization process is carried out for the minimization of the drag coefficient and maximization of lift to drag ratio. In-house MATLAB code is incorporated with a genetic algorithm to calculate the drag coefficient and lift to drag ratio of the resulting optimized airfoil. The panel method is utilized in genetic algorithm optimization code to calculate pressure distribution, lift coefficient, and lift to drag ratio for optimized airfoil shapes and validates with XFOIL and NREL experimental data. Furthermore, CFD analysis is conducted for both the original (NREL S-821) and optimized airfoil obtained. The present method shows that the optimized airfoil achieved an improvement in lift to drag ratio by 7.4% and 15.9% of S-821 and RAE-2822 airfoil, respectively, by the panel technique method and provides high design desirable stability parameters. These features significantly improve the overall aerodynamic performance of the newly optimized airfoils. Finally, the improved aerodynamics results are reported for the design of turbulence modeling and NREL phase II, Phase III, and Phase VI HAWT blades.

scholarly journals Aerodynamic Shape Optimization of NREL S809 Airfoil for Wind Turbine Blades Using Reynolds-Averaged Navier Stokes Model—Part II

2021 ◽  
Vol 11 (5) ◽  
pp. 2211
Author(s):  
Md Tausif Akram ◽  
Man-Hoe Kim
Keyword(s):  
Wind Turbine ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Phase Iii ◽  
Navier Stokes ◽  
Wind Turbine Blades ◽  
Shape Transformation ◽  
Reynolds Averaged Navier Stokes ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Sustainability has become one of the most significant considerations in everyday work, including energy production. The fast-growing trend of wind energy around the world has increased the demand for efficient and optimized airfoils, which has paved the way for energy harvesting systems. The present manuscript proposes an aerodynamically optimized design of the well-known existing NREL S809 airfoil for performance enhancement of the blade design for wind turbines. An integrated code, based on a genetic algorithm, is developed to optimize the asymmetric NREL S809 airfoil by class shape transformation (CST) and the parametric section (PARSEC) parameterization method, analyzing its aerodynamic properties and maximizing the lift of the airfoil. The in-house MATLAB code is further incorporated with XFOIL to calculate the coefficient of lift, coefficient of drag and lift-to-drag ratio at angles of attack of 0° and 6.2° by the panel technique and validated with National Renewable Energy Laboratory (NREL) experimental results provided by The Ohio State University (OSU). On the other hand, steady-state CFD analysis is performed on an optimized S809 airfoil using the Reynolds-averaged Navier–Stokes (RANS) equation with the K–ω shear stress transport (SST) turbulent model and compared with the experimental data. The present method shows that the optimized airfoil by CST is predicted, with an increment of 11.8% and 9.6% for the lift coefficient and lift-to-drag ratio, respectively, and desirable stability parameters obtained for the design of the wind turbine blades. These characteristics significantly improve the overall aerodynamic performance of new optimized airfoils. Finally, the aerodynamically improved results are reported for the design of the NREL Phase II, Phase III and Phase VI HAWT blades.

scholarly journals Shape Optimization of NREL S809 Airfoil for Wind Turbine Blades Using a Multiobjective Genetic Algorithm

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Yilei He ◽  
Ramesh K. Agarwal
Keyword(s):  
Genetic Algorithm ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Optimization Technique ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Multiobjective Genetic Algorithm ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The goal of this paper is to employ a multiobjective genetic algorithm (MOGA) to optimize the shape of a well-known wind turbine airfoil S809 to improve its lift and drag characteristics, in particular to achieve two objectives, that is, to increase its lift and its lift to drag ratio. The commercially available software FLUENT is employed to calculate the flow field on an adaptive structured mesh using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a two-equationk-ωSST turbulence model. The results show significant improvement in both lift coefficient and lift to drag ratio of the optimized airfoil compared to the original S809 airfoil. In addition, MOGA results are in close agreement with those obtained by the adjoint-based optimization technique.

An Investigation of Drag Reduction on Gurney Flaps by an Three-Element Airfoil

2011 ◽  
Vol 138-139 ◽  
pp. 229-233
Author(s):  
Pei Qing Liu ◽  
Shuo Yang ◽  
Yun Tian
Keyword(s):  
Drag Coefficient ◽  
Aerodynamic Characteristic ◽  
Lift Force ◽  
Lift Coefficient ◽  
Simulation Method ◽  
High Lift ◽  
Gurney Flap ◽  
Different Types ◽  
Drag Ratio ◽  
Lift To Drag Ratio

During airplane’s take-off, higher lift force should be provided by wing used high lift devices, and the drag should be lower. The design basis of high lift devices with good aerodynamic characteristic is the design of the multi-element airfoil. When a multi-element airfoil is used Gurney flap, lift coefficient can be improved while drag coefficient is also increased, but the lift-to-drag ratio is reduced. In this paper, the numerical simulation method is used to study the aerodynamic characteristic of the multi-element airfoil used Gurney flap with slat in the configuration of take-off. Lift coefficient and drag coefficient of the multi-element airfoil with Gurney flap can be reduced by slat while lift-to-drag ratio of airfoil is increased. Through the comparisons of the multi-element airfoils with Gurney flap with different types of slats, the optimized multi-element airfoil with higher lift coefficient and lower drag coefficient is obtained ultimately.

Wind Tunnel Experiment for Low Wind Speed Wind Turbine Blade

2011 ◽  
Vol 110-116 ◽  
pp. 1589-1593
Author(s):  
Mohd Noh Mohd Hafiz ◽  
Abdul Hamid Ahmad Hussein ◽  
Rashid Helmi ◽  
Wisnoe Wirachman ◽  
Syahmi Nasir Mohd
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Early Stage ◽  
Lift Coefficient ◽  
Green Energy ◽  
Wind Tunnel Experiment ◽  
Energy Awareness ◽  
Maximum Thickness ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Environment and green energy awareness are two main factors why this study has been carried out. This research is focused on aerodynamics study for airfoil structure modification based on NACA 0044 and NACA 0063 by using wind tunnel experiment. Aerodynamic characteristics such as lift coefficient, CL, drag coefficient, CD, lift to drag ratio and cell relative velocity has been investigated in this study. CFD simulation has been carried out at the early stage of the investigation (for NACA 0044 and NACA 0063), and a new airfoil profile had been created (0044-63) by modified the chord length and the location of maximum thickness of the airfoil by using the modified NACA Four-Digit Series. Wind tunnel experiment has been take place for three different wind speeds from 25m/s, 35m/s and 45m/s at various angles of attack from 0o to 40o with 5o incremental for the respective airfoil. The results show that the modified 0044-63 produced the better lift coefficient and this airfoil has been fabricated and tested in the wind tunnel experiment in order to validate the CFD result. This paper reports the result of aerodynamics characteristics for respective new airfoil and it shows that at angle of attack between 5 o to 15 o, this airfoil produced good lift to drag ratio value. Also, by modified the location of maximum thickness 30% to the trailing edge give the increment of lift to drag ratio produced approximately 15% and at the same time, give insignificant changes to the drag coefficient value.

scholarly journals Lift and Drag Coefficient Map of NACA4415 Airfoil

2021 ◽  
Vol 2076 (1) ◽  
pp. 012066
Author(s):  
Rui Yin ◽  
Jing Huang ◽  
Zhi-Yuan He
Keyword(s):  
Reynolds Number ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Optimal Angle ◽  
Fluent Software ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract The NACA4415 airfoil was numerically simulated with the help of the Fluent software to analyze its aerodynamic characteristics. Results are acquired as follows: The calculation accuracy of Fluent software is much higher than that of XFOIL software; the calculation result of SST k-ω(sstkw) turbulence model is closest to the experimental value; within a certain range, the larger the Reynolds number is, the larger the lift coefficient and lift-to-drag ratio of the airfoil will be, and the smaller the drag coefficient will be; when the angle of attack is less than the optimal angle of attack, the Reynolds number has less influence on the lift-to-drag coefficient and the lift-to-drag ratio; as the Reynolds number increases, the optimal angle of attack increases slightly, and the applicable angle of attack range for high lift-to-drag ratios becomes smaller.

scholarly journals Effects of Pitching Motion Elements on Aerodynamic Characteristics of Airfoil

2021 ◽  
Vol 2076 (1) ◽  
pp. 012078
Author(s):  
Rui Yin ◽  
Jing Huang ◽  
Zhi-Yuan He
Keyword(s):  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Initial Angle ◽  
Pitching Motion ◽  
The Difference ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract The aerodynamic characteristics of NACA4412 airfoil with different pitching motion elements were compared and analyzed based on CFD in this research. The results are acquired as follows: the difference between the lift and drag coefficients of the airfoil during pitch up and pitch down motions becomes larger with the increase of the pitching amplitude or initial angle of attack; as the pitching amplitude increases, the lift coefficient grows slightly greater and the drag coefficient grows much greater; as the initial angle of attack increases, the lift coefficient grows much greater and the drag coefficient grows slightly; the smaller the attenuation frequency is, the larger the lift-to-drag ratio of the airfoil will be.

scholarly journals Experimental Determination of the Impact of Floats on the Aerodynamic Characteristics of an OSA Model in Symmetric Flow

2021 ◽  
Vol 12 (1) ◽  
pp. 41-58
Author(s):  
Michał FRANT ◽  
Stanisław WRZESIEŃ ◽  
Maciej MAJCHER
Keyword(s):  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Symmetric Flow ◽  
Aerodynamic Drag Coefficient ◽  
The Impact ◽  
Drag Ratio ◽  
Lift To Drag Ratio

This paper presents the results of experimental determination of the impact of floats on the aerodynamic characteristics of an OSA model in symmetric flow. The studies have been performed in the low-speed wind tunnel at the Military University of Technology (MUT, Warsaw, Poland). The aircraft model was examined at the dynamic pressure q = 500 Pa in the following angle of attack range = -2828. The investigations have been performed for an aircraft model under plain configuration with floats and without floats. The influence of elevator and flap inclination on the aerodynamic characteristics of the model has also been analysed. The obtained values of aerodynamic drag coefficient, lift coefficient, pitching moment coefficient and lift-to-drag ratio have been presented in the form of tables and graphs. The studies performed demonstrated that the use of floats causes the increase of aerodynamic drag coefficient CD, maximum lift coefficient CLmax as well as critical angle of attack cr. The decrease of lift-to-drag ratio has also been observed. Its value in the case of the model with floats was up to 20% lower than in the model without floats. The studies also showed that the model equipped with floats had a lower longitudinal static stability margin than the model without floats.

scholarly journals Shape Optimization of an Airfoil in Ground Effect for Application to WIG Craft

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yilei He ◽  
Qiulin Qu ◽  
Ramesh K. Agarwal
Keyword(s):  
Genetic Algorithm ◽  
Flow Field ◽  
Lift Coefficient ◽  
Ground Effect ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Multiobjective Genetic Algorithm ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

This paper employs a multiobjective genetic algorithm (MOGA) to optimize the shape of a widely used wing in ground (WIG) aircraft airfoil NACA 4412 to improve its lift and drag characteristics, in particular to achieve two objectives, that is, to increase its lift and its lift to drag ratio. The commercial software ANSYS FLUENT is employed to calculate the flow field on an adaptive structured mesh generated by ANSYS ICEM software using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a one equation Spalart-Allmaras (SA) turbulence model. The results show significant improvement in both the lift coefficient and lift to drag ratio of the optimized airfoil compared to the original NACA 4412 airfoil. It is demonstrated that the performance of a wing in ground (WIG) aircraft can be improved by using the optimized airfoil.

Genetic Algorithm-Based Design of Airfoil for the Root Region of Small Wind Turbines and Performance Analysis With Gurney Flaps

2018 ◽  
Author(s):  
Mohammed Rafiuddin Ahmed ◽  
Krishnil R. Ram ◽  
Bum-Suk Kim ◽  
Sunil P. Lal
Keyword(s):  
Genetic Algorithm ◽  
Wind Turbines ◽  
Lift Coefficient ◽  
Lower Surface ◽  
Trailing Edge ◽  
Gurney Flaps ◽  
Root Region ◽  
Small Wind Turbines ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The root region of small wind turbines experience low Reynolds number (Re) flow that makes it difficult to design airfoils that provide good aerodynamic performance and at the same time, provide structural strength. In the present work, a multi-objective genetic algorithm code was used to design airfoils that are suitable for the root region of small wind turbines. A composite Bezier curve with two Bezier segments and 16 control points (11 of them controlled) was used to parametrize the airfoil problem. Geometric constraints including suitable curvature conditions were enforced to maintain the airfoil thickness between 18% and 22% of chord and a trailing edge thickness of 3% of chord. The objectives were to maximize the lift-to-drag ratio for both clean and soiled conditions. Optimization was done by coupling the flow solver to a genetic algorithm code written in C++, at Re = 200,000 and for angles of attack of 4 and 10 degrees, as the algorithm was found to give smooth variation of lift-to-drag ratio within such a range. The best airfoil from the results was tested in the wind tunnel as well as using ANSYS-CFX. The experimental airfoil had a chord length of 75 mm and was provided with 33 pressure taps. Testing was done for both free and forced transition cases. The airfoil gave the highest lift-to-drag ratio at an angle of 6 degrees with the ratio varying very little between 4 degrees and 8 degrees. Forced transition at 8% of chord did not show significant change in the performance indicating that the airfoil will perform well even in soiled condition. Fixed trailing edge flaps (Gurney flaps) were provided right at the trailing edge on the lower surface. The lift and drag behavior of the airfoil was then studied with Gurney Flaps of 2% and 3% heights, as it was found from previous studies that flap heights of 1% or greater than 3% do not give optimum results. The flaps considerably improved the suction on the upper surface and also improved the pressure on the lower surface, resulting in a higher lift coefficient; at the same time, there was also an increase in the drag coefficient but it was less compared to the increase in the lift coefficient. The results indicate that Gurney flaps can be effectively used to improve the performance of thick trailing edge airfoils designed for the root region of small wind turbines.

CFD Simulation of the Flow Characteristics of NACA 0012, NACA 6409, and DHMTU Airfoils in Ground Effect

2014 ◽  
Author(s):  
Saurabh Sharma ◽  
Shibu Clement
Keyword(s):  
Drag Coefficient ◽  
Cfd Simulation ◽  
Computational Study ◽  
Lift Coefficient ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Ground Effect ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Ground effect is a phenomenon caused by the presence of a fixed boundary layer below a wing. This results in an effective increase in lift to drag ratio of the airfoil. The available literature on this phenomenon is very limited; also the types of airfoils used in traditional aircrafts are not suited for ground effect vehicles, so a computational study has been done comparing traditional airfoils (NACA series) with ground effect airfoil (DHMTU). In this paper, the aerodynamic characteristics of a NACA 6409, NACA 0012, DHMTU 12-35.3-10.2-80.12.2[1] section in ground effect were numerically studied and compared. In 2D simulation, the flow around each of the airfoils has been investigated for different turbulence models viz. Spalart Allmaras turbulence model and k-ε Realizable turbulence models. Lift coefficient, drag coefficient, pitching moment coefficient and lift to drag ratio of each airfoil was determined on several angles of attack from 0 to 10° (0°, 2°, 4°, 6°, 8°, 10°) and different ground clearances (h/c=0.2, 0.4, 0.6, 0.8, 1.0). The results of the CFD simulation indicate a reduction in drag coefficient and an increase in lift coefficient, thus an overall increment in lift to drag ratio of the airfoils, when flying in proximity to the ground. Also DHMTU airfoils have shown a greater consistency in Cm behavior with decreasing height-to-chord (h/c) ratio.

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