Airfoil Shape and Angle of Attack Optimization Based On Bézier Curve and Multi-Island Genetic Algorithm

2021 ◽  
Author(s):  
Jiabing Wang ◽  
Chaochen Wang ◽  
Bowen Zhou ◽  
Linlang Zeng ◽  
Kun Yang
Keyword(s):  
Genetic Algorithm ◽  
Angle Of Attack ◽  
Reynolds Numbers ◽  
Aerodynamic Characteristics ◽  
Bézier Curve ◽  
Bezier Curve ◽  
Optimal Angle ◽  
Wide Range ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract In order to improve the aerodynamic performance of the airfoil, the airfoil shape and the angle of attack (AOA) are optimized at the same time by the Multi-island Genetic Algorithm in this paper. The goal of the optimization is to maximize the lift-to-drag ratio which is calculated by computational fluid dynamics method. The airfoil is parameterized by the Bézier curve. The thickness and the camber of airfoil are no longer restricted to ensure a wide range of airfoil generation. The airfoil is optimized under different Reynolds numbers. The optimized airfoils obtained by the unconstrained AOA method are compared with several standard airfoils. The results show that the maximum lift-to-drag ratio of the optimized airfoil is much greater than the compared airfoils, and the optimized airfoils have good aerodynamic characteristics in a wide range of angle of attack. By comparing with the optimized airfoils obtained by the constrained AOA method, it shows that the constrained AOA method can't guarantee that the pre-constrained angle of attack is the optimal angle of attack of the airfoil, nor can obtain the maximum lift-to-drag ratio airfoil of all angles of attack and all airfoils. However, by using the angle of attack as one of the optimization variables, these problems can be solved well.

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 Aerodynamic and Vibration Characteristics of the Micro-Octocopter at Low Reynolds Number

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Xiaohua Zou ◽  
Mingsheng Ling ◽  
Wenzheng Zhai
Keyword(s):  
Reynolds Number ◽  
Load Capacity ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Vibration Characteristics ◽  
Low Reynolds ◽  
Vibration Performance ◽  
Drag Ratio ◽  
Lift To Drag Ratio

With the development of flight technology, the need for stable aerodynamic and vibration performance of the aircraft in the civil and military fields has gradually increased. In this case, the requirements for aerodynamic and vibration characteristics of the aircraft have also been strengthened. The existing four-rotor aircraft carries limited airborne equipment and payload, while the current eight-rotor aircraft adopts a plane layout. The size of the propeller is generally fixed, including the load capacity. The upper and lower tower layout analyzed in this paper can effectively solve the problems of insufficient four-axis load and unstable aerodynamic and vibration performance of the existing eight-axis aircraft. This paper takes the miniature octorotor as the research object and studies the aerodynamic characteristics of the miniature octorotor at different low Reynolds numbers, different air pressures and thicknesses, and the lift coefficient and lift-to-drag ratio, as well as the vibration under different elastic moduli and air pressure characteristics. The research algorithm adopted in this paper is the numerical method of fluid-solid cohesion and the control equation of flow field analysis. The research results show that, with the increase in the Reynolds number within a certain range, the aerodynamic characteristics of the miniature octorotor gradually become better. When the elastic modulus is 2.5 E, the aircraft’s specific performance is that the lift increases, the critical angle of attack increases, the drag decreases, the lift-to-drag ratio increases significantly, and the angle of attack decreases. However, the transition position of the flow around the airfoil surface is getting closer to the leading edge, and its state is more likely to transition from laminar flow to turbulent flow. When the unidirectional carbon fiber-reinforced thickness is 0.2 mm and the thin arc-shaped airfoil with the convex structure has a uniform thickness of 2.5% and a uniform curvature of 4.5%, the aerodynamic and vibration characteristics of the octorotor aircraft are most beneficial to flight.

Optimization of Maximum Lift to Drag Ratio on Airfoil Design Based on Artificial Neural Network Utilizing Genetic Algorithm

2014 ◽  
Vol 493 ◽  
pp. 123-128 ◽  
Author(s):  
Ismoyo Haryanto ◽  
Tony Suryo Utomo ◽  
Nazaruddin Sinaga ◽  
Citra Asti Rosalia ◽  
Aditya Pratama Putra
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Artificial Neural Network ◽  
Design Method ◽  
Aerodynamic Characteristics ◽  
Drag Coefficients ◽  
Artificial Neural ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

.This paper deals with an alternative design method of airfoil for wind turbine blade for low wind speed based on combination of smart computing and numerical optimization. In this work, a simulation of Artificial Neural Network (ANN) for determining the relation between airfoil geometry and its aerodynamic characteristics was conducted. First, several airfoil geometries were generated through transformation of complex variables (Joukowski transformation), and then lift and drag coefficients of each airfoil were determined using CFD (Computational Fluid Dynamics). In present study, the ANN training was conducted using airfoil geometry and its aerodynamic characteristics as input and output, respectively. Therefore, lift and drag coefficients can be directly determined only by giving the airfoil geometry without having to perform wind tunnel experiment or numerical computation. Moreover, the optimization was conducted to obtain an airfoil geometry which gives maximum lift to drag ratio (CL/CD) for specific Reynolds number. For this purpose Genetic Algorithm (GA) was applied as optimizer. The results were validated using commercial CFD and it can be shown that the result are satisfactory with error approximately of 6%.

scholarly journals Computational Investigation of Aerodynamic Characteristics for Elliptic UAVs’ Wing

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
Amaal Attiah ◽  
Ibrahim Elbadawy ◽  
Osama E. Mahmoud
Keyword(s):  
Reynolds Number ◽  
Computational Study ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Thickness Ratio ◽  
Ansys Fluent ◽  
Rotor Wing ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Elliptic Airfoil

Unmanned Aerial Vehicles, UAVs, gained an important role in modern military and civilian applications. Developments in UAVs technology improve its performance and maneuverability with acceptable cost. Elliptic airfoil had been widely used in the development of Rotor/Wing subsonic aircraft. The present work aims to investigate the effect of various elliptic airfoil parameters, such as Reynolds number, angle of attack and airfoil thickness, on aerodynamic behavior using two-dimensional computational study. The computational results were validated by experimental results. Angles of attack was evaluated from 0° to 18° in order to analyze aerodynamic characteristics up to stall condition, while Reynolds number was evaluated at values of 1×10⁵, 3×105, 2×106, and 8×106, to cover the range of rotary and fixed wing flight conditions. Thickness ratio was ranged from 5% to 25% to include the UAVs airfoil thicknesses so that choice best thickness gets max lift to drag ratio. In addition, the thicknesses location was evaluated for a range of 30% to 70% to get suitable location gets max left to drag ratio. The ANSYS-Fluent software was used with Spalart-Allmaras turbulence model, and found that the maximum lift to drag ratio which improve the UAV capability in this study is at Re=2×106, angle of attack at 8°, max thickness ratio of (0.1chord) located at (0.3chord).

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 Numerical study on aerodynamic performance of waverider with a new bluntness method

2020 ◽  
pp. 095441002096841
Author(s):  
Zhipeng Qu ◽  
Houdi Xiao ◽  
Mingyun Lv ◽  
Guangli Li ◽  
Cui Kai
Keyword(s):  
Numerical Study ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
The Novel ◽  
High Lift ◽  
Wide Range ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Sharp Leading Edge

Abastrct The waverider is deemed the most promising configuration for hypersonic vehicle with its high lift-to-drag ratio at design conditions. However, considering the serious aero-heating protection, the sharp leading edge must be blunted. The existing traditional bluntness methods including the following two types: “reducing material method” and “adding material method”. Compared to the initial waverider, the volume will be smaller or larger using the traditional methods. With the fixed blunted radius, the volume and aerodynamic performance is determined. In this paper, a new bluntness method which is named “mixing material method” is developed. In this new method, a new parameter is introduced based on the traditional two bluntness methods. Under fixed blunted radius, the volume and aerodynamic performance can be changed within a wide range by adjusting the parameter. When the parameter is 0 and 1, the novel blunted method degenerated into the “reducing material method” and “adding material method” respectively. The influence of new parameter on the aerodynamic characteristics and volume are studied by numerical simulation. Results show that the volume, lift and lift-to-drag ratio increases with the increase of the parameter under the fixed blunt radius, but simultaneously, the drag will also increase. Therefore, considering the different requirements of the air-breathing hypersonic aircrafts for the balance of thrust and drag, lift and weight, a suitable bluntness parameter can be selected to achieve a balance. This research can provide reference for hypersonic waverider vehicle design.

Aerodynamic study of single corrugated variable-camber morphing aerofoil concept

2021 ◽  
pp. 1-29
Author(s):  
K. Dhileep ◽  
D. Kumar ◽  
P.N. Gautham Vigneswar ◽  
P. Soni ◽  
S. Ghosh ◽  
...  
Keyword(s):  
Finite Volume ◽  
Interpolation Method ◽  
Beam Theory ◽  
Small Deformation ◽  
Aerodynamic Characteristics ◽  
Ansys Fluent ◽  
Aerodynamic Efficiency ◽  
Finite Element Software ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract Camber morphing is an effective way to control the lift generated by any aerofoil and potentially improve the range (as measured by the lift-to-drag ratio) and endurance (as measured by $C_l^{3/2}/C_d$ ). This can be especially useful for fixed-wing Unmanned Aerial Vehicles (UAVs) undergoing different flying manoeuvres and flight phases. This work investigates the aerodynamic characteristics of the NACA0012 aerofoil morphed using a Single Corrugated Variable-Camber (SCVC) morphing approach. Structural analysis and morphed shapes are obtained based on small-deformation beam theory using chain calculations and validated using finite-element software. The aerofoil is then reconstructed from the camber line using a Radial Basis Function (RBF)-based interpolation method (J.H.S. Fincham and M.I. Friswell, “Aerodynamic optimisation of a camber morphing aerofoil,” Aerosp. Sci. Technol., 2015). The aerodynamic analysis is done by employing two different finite-volume solvers (OpenFOAM and ANSYS-Fluent) and a panel method code (XFoil). Results reveal that the aerodynamic coefficients predicted by the two finite-volume solvers using a fully turbulent flow assumption are similar but differ from those predicted by XFoil. The aerodynamic efficiency and endurance factor of morphed aerofoils indicate that morphing is beneficial at moderate to high lift requirements. Further, the optimal morphing angle increases with an increase in the required lift. Finally, it is observed for a fixed angle-of-attack that an optimum morphing angle exists for which the aerodynamic efficiency becomes maximum.

scholarly journals Study of board bending degree on hydrodynamic performances of a single-layer cambered otter-board

2019 ◽  
Vol 131 ◽  
pp. 01120
Author(s):  
Lei Wang ◽  
Lu Min Wang ◽  
Yong Li Liu ◽  
Wen Wen Yu ◽  
Guang Rui Qi ◽  
...  
Keyword(s):  
Center Of Pressure ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Angle Of Attack ◽  
Single Layer ◽  
Moment Coefficient ◽  
Pitch Moment ◽  
Engineering Models ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The effect of board bending degree on hydrodynamic performances of a single-layer cambered otter-board was investigated using engineering models in a wind tunnel. Three different bending degree boards were evaluated at a wind speed of 28 m/s. Parameters measured included: drag coefficient Cx, lift coefficient Cy, pitch moment coefficient Cm, center of pressure coefficient Cp , over a range of angle of attack (0° to 70°). These coefficients were used in analyzing the differences in the performance among the three otter-board models. Results showed that the bending of the board(No. 2, No. 3) increased the water resistance of the otter-board, and improved the lift coefficient of the otter-board in the small angle of attack (0°<α≤20 °) ; the maximum lift coefficients Cy of otter-board model (No. 1) was higher (1.680, α = 25°). the maximum lift–drag ratios of models (No. 1, No. 2 and No. 3) are 6.822 (α = 7.5 °), 6.533 (α = 2.5 °) and 6.384 (α = 5.0°), which showed that the board bending reduces the lift-to-drag ratio of the otter-board.The stability of the No. 3 model was better than those two models (No. 1, No. 2) in most range of attack angle, but No. 1 otter-board model had a better stability in roll of otter-board. The findings of this study can offer useful reference data for the structural optimization of otter-boards for trawling.

Aerodynamic characteristics of breathing blunt nose configuration at hypersonic speeds

2016 ◽  
Vol 231 (5) ◽  
pp. 840-858 ◽  
Author(s):  
Yasumasa Watanabe ◽  
Kojiro Suzuki ◽  
Ethirajan Rathakrishnan
Keyword(s):  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Positive Pressure ◽  
Stagnation Region ◽  
Total Drag ◽  
Hypersonic Speeds ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Blunt Nose

Breathing blunt nose technique is one of the promising methods for reducing the drag of blunt-nosed body at hypersonic speeds. The air, traversed by the bow shock positioned ahead of the nose, at the stagnation region is allowed to enter through a hole at the blunt-nose and ejected at the rear part (base region) of the body. This manipulation reduces the positive pressure over the stagnation regions of the nose and increases the pressure at the base, resulting in reduced suction at the base. The simultaneous manifestation of reducing the compression at the nose and suction at the base regions results in reduction of the total drag. The drag reduction caused by the breathing blunt nose technique has been measured in a Mach 7 tunnel. Also, the drag and flow field around the blunt-nosed body, with and without breathing hole, has been computed. The aerodynamic characteristics of the breathing blunt nose model obtained experimentally are compared with the CFD results. It is found that the breathing results in 5% reduction in drag. The lift coefficient also comes down for the model with breathing nose. But the lift-to-drag ratio is found to be the same for both the cases; the blunt-nosed body with and without nose-hole.

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