The aerodynamic optimisation of a low-Reynolds paper plane with adjoint method

2020 ◽  
pp. 1-15
Author(s):  
Y. Zhang ◽  
X. Zhang ◽  
G. Chen
Keyword(s):  
Adjoint Method ◽  
Low Cost ◽  
Aerodynamic Performance ◽  
Discrete Adjoint ◽  
Design Variables ◽  
Limited Variation ◽  
Aerial Vehicle ◽  
Paper Plane ◽  
Drag Ratio ◽  
Lift To Drag Ratio

ABSTRACT The aerodynamic performance of a deployable and low-cost unmanned aerial vehicle (UAV) is investigated and improved in present work. The parameters of configuration, such as airfoil and winglet, are determined via an optimising process based on a discrete adjoint method. The optimised target is locked on an increasing lift-to-drag ratio with a limited variation of pitching moments. The separation that will lead to a stall is delayed after optimisation. Up to 128 design variables are used by the optimised solver to give enough flexibility of the geometrical transformation. As much as 20% enhancement of lift-to-drag ratio is gained at the cruise angle-of-attack, that is, a significant improvement in the lift-to-drag ratio adhering to the preferred configuration is obtained with increasing lift and decreasing drag coefficients, essentially entailing an improved aerodynamic performance.

Aerofoil profile and sweep optimisation for a blended wing-body aircraft using a discrete adjoint method

2006 ◽  
Vol 110 (1111) ◽  
pp. 589-604 ◽  
Author(s):  
A. Le Moigne ◽  
N. Qin
Keyword(s):  
Sequential Quadratic Programming ◽  
Adjoint Method ◽  
Navier Stokes ◽  
High Fidelity ◽  
Sweep Angle ◽  
Sqp Method ◽  
Discrete Adjoint ◽  
Design Variables ◽  
Variable Fidelity ◽  
Blended Wing Body

Abstract Aerodynamic optimisations of a blended wing-body (BWB) aircraft are presented. A discrete adjoint solver is used to calculate efficiently the gradients, which makes it possible to optimise for a large number of design variables. The optimisations employ either a variable-fidelity method that combines low- and high-fidelity models or a direct sequential quadratic programming (SQP) method. Four Euler optimisations of a BWB aircraft are then presented. The optimisation is allowed to change a series of master sections defining the aircraft geometry as well as the sweep angle on the outer wing for two of the optimisations. Substantial improvements are obtained, not only in the Euler mode but also when the optimised geometries are evaluated using Reynolds-averaged Navier-Stokes solutions. Some interesting features of the optimised wing profiles are discussed.

Numerical Study of Improving Aerodynamic Performance of the Cylinder Airfoil of Magnus Wind Turbine

2013 ◽  
Vol 650 ◽  
pp. 414-419
Author(s):  
Qi Yao ◽  
Ying Xue Yao ◽  
Liang Zhou ◽  
Jin Ming Wu ◽  
Jian Guang Li
Keyword(s):  
Fluid Dynamics ◽  
Drag Force ◽  
Numerical Study ◽  
Rotating Cylinder ◽  
Aerodynamic Performance ◽  
Orthogonal Test ◽  
Performance Change ◽  
Result Show ◽  
Drag Ratio ◽  
Lift To Drag Ratio

To solve the problem of low lift to drag ratio of Magnus cylinder airfoil, the Computational Fluid Dynamics software Fluent was used to study the principle of a drop of the drag force of cylinder when rotating. And the principle was used to further reduce the drag of rotating cylinder. A traditional airfoil head and a triangle tail was used to study the effect of the aerodynamic performance change of the combined airfoil. A conclusion was made that with a suitable profile of the tail would reduce the drag force of the combined airfoil thus increase the lift to drag ratio of the airfoil. At last an orthogonal test was made to determine the size of the tail airfoil. The result show that the optimized airfoil reduce the drag force to 50% of the original cylinder and improve the lift to drag ratio to 50%.

Research on Improved Method of Wind Turbine Airfoil S834 Based on Noise and Aerodynamic Performance

2015 ◽  
Vol 744-746 ◽  
pp. 253-258 ◽  
Author(s):  
Ya Qiong Chen ◽  
Yue Fa Fang
Keyword(s):  
Wind Turbine ◽  
Optimization Design ◽  
Design Method ◽  
Aerodynamic Performance ◽  
Parametric Modeling ◽  
Multi Objective ◽  
Wind Turbine Airfoil ◽  
Drag Ratio ◽  
Operating Points ◽  
Lift To Drag Ratio

In this paper, aerodynamic performance and noise of the wind turbine airfoil are the optimization design goal and based on this, the optimization design method with multi-operating points and multi-objective of the airfoils is built. The Bezier curve is used in parametric modeling of the contour of the airfoil and the general equation for control points is deduced form the discrete points coordinates of the airfoil. The weigh distribution schemes for multi-objective and multi-operating points are integrated designed by treating the NREL S834 airfoil as the initial airfoils. The results show that the lift-to-drag ratio of the optimized airfoils has a improvement around the designed operating angle and the overall noise has a reduction compared with the initial airfoils, which means that the optimized airfoils get a better aerodynamic and acoustic performance.

Numerical and Experiment Study on New Types of Magnus Blade

2014 ◽  
Vol 472 ◽  
pp. 271-275
Author(s):  
Ying Xue Yao ◽  
Xue Wen Wang ◽  
Jin Ming Wu
Keyword(s):  
Wind Turbine ◽  
Simple Structure ◽  
Low Cost ◽  
Fossil Energy ◽  
Low Wind Speed ◽  
2D Simulation ◽  
New Energy ◽  
New Type ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Fossil energy is becoming less and less, as one of new energy, many countries pay more attention on wind energy. Magnus wind turbine has an advantage of simple structure, low cost. It can work well at a very low wind speed and the control system is very simple. As the cylinder blade of traditional Magnus wind turbine has a relatively low lift to drag ratio, This paper provide two new type blade of Magnus wind turbine and it can greatly improve lift to drag ratio of Magnus wind turbine. This paper will use CFD software Fluent, through 2D simulation, compare the lift to drag ratio of cylinder blades. At last, do experiments to compare the performance of these blades.

Aerodynamic Optimization and Inverse Design of 2D and 3D Turbine Cascades Using the Discrete Adjoint Method

2013 ◽  
Author(s):  
Juan Lu ◽  
Chaolei Zhang ◽  
Zhenping Feng
Keyword(s):  
Design Optimization ◽  
Optimization Design ◽  
Adjoint Method ◽  
Inverse Design ◽  
Aerodynamic Design ◽  
Discrete Adjoint ◽  
Design Variables ◽  
Discrete Adjoint Method ◽  
Turbine Cascades ◽  
2D And 3D

The adjoint method has significant advantage in sensitivity analysis because its computation cost is independent of the number of the design variables. In recent years it has been applied greatly in aerodynamic design optimization of turbomachinery. This paper developed the discrete adjoint method based on the authors’ previous work and demonstrated the applications of the method in the aerodynamic design optimization for turbine cascades. The Non-uniform Rational B-Spline (NURBS) technology was introduced in the current design optimization system and a flexible parameterization method for 3D cascade was proposed. Based on the parameterization method, the stack line and the blade profile are parameterized together by using NURBS curves. During the design process, the control points of the profile, the stack point and the stagger angle of the blade on each section can be taken as the design variables. Moreover, the flow solver and the discrete adjoint solver were extended towards the turbulent flow environment by adopting the k – ω turbulence model. Based on the optimization design system, several applications including two optimization design cases and two inverse design cases for 2D and 3D turbine cascades were implemented with the mass flow ratio constraint. The gradient verification and the numerical cases showed the correctness and accuracy of the discrete adjoint solver. The numerical results demonstrated the validity and efficiency of the design optimization system based on discrete adjoint method.

scholarly journals APPROXIMATE ASSESSMENT OF THE OPERATIONAL PERFORMANCES OF AN UNMANNED AERIAL VEHICHLE ACCORDING TO ITS FLIGHT DATA

Aviation ◽  
2016 ◽  
Vol 19 (4) ◽  
pp. 187-193 ◽  
Author(s):  
Valeriy Silkov ◽  
Mykola Delas
Keyword(s):  
Fuel Consumption ◽  
Unmanned Aerial Vehicle ◽  
Comparative Assessment ◽  
Flight Duration ◽  
Flight Data ◽  
Flight Range ◽  
Different Types ◽  
Aerial Vehicle ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The article is dedicated to the substantiation of the complex parameter that characterizes the technical level of an unmanned aerial vehicle (UAV). This parameter includes the maximum lift-to-drag ratio, propeller efficiency, specific fuel consumption, and other components, on which the main flight characteristics, such as flight range and flight duration, depend. To make a comparative assessment of UAVs of different types, a special scale is developed.

Modification impact on aerodynamic performance of hypersonic waverider

2011 ◽  
Vol 115 (1168) ◽  
pp. 325-334 ◽  
Author(s):  
C. Xiao-Qing ◽  
H. Zhong-Xi ◽  
L. Jian-Xia ◽  
G. Xian-Zhong
Keyword(s):  
Leading Edge ◽  
Aerodynamic Performance ◽  
Hypersonic Vehicles ◽  
Flow Conditions ◽  
Aerodynamic Coefficient ◽  
High Lift ◽  
Computational Fluid Dynamics Cfd ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Sharp Leading Edge

Abstract Waverider serves as a good candidate for hypersonic vehicles. The typical waverider has sharp leading edge and no control face, which is inappropriate for practical use. This paper puts forward a method modifying the waverider, and the modification impact on the performance of waverider at hypersonic flow conditions is studied. The modification is based on blunted waverider, includes cutting the tip and introducing two control wings. The modification’s effect on aerodynamic performance is obtained and analysed through Computational Fluid Dynamics (CFD) techniques. When blunted with 2cm radius, the waverider retains its good aerodynamic performance and the heat flux at the stagnation point can be managed. Three factors of the introduced wing are argued, the fixed angle, aspect ratio and wing area. Results show that influence on the aerodynamic coefficient is slight and the vehicle retains its high lift-to-drag ratio. The main influences of the modification are the control ability and trim efficiency, which is the motivation of this work and can be adapted when designing a practical waverider.

scholarly journals RESEARCH OF WING DIHEDRAL ANGLE EFFECT ON AERODYNAMIC PERFORMANCE OF TANDEM-WING UNMANNED AERIAL VEHICLE

2013 ◽  
pp. 90-101
Author(s):  
І. С. Кривохатько
Keyword(s):  
Dihedral Angle ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Theoretical Explanation ◽  
Wing Span ◽  
Induced Drag ◽  
Rear Wing ◽  
Angle Effect ◽  
Drag Ratio ◽  
Lift To Drag Ratio

In the last decade folding tube launch UAV became common, for which aerodynamic scheme "tandem" is reasonable. By the time tandem-wing aerodynamic characteristics are researched much less than ones of traditional scheme. Particularly it concerns wing dihedral angle effect on lift-to-drag ratio about which no quantitative data were found.Forward or rear wing dihedral angle appearance result in circulation redistribution and changing of rear wing induced drag. Rear wing dihedral angle effect on longitudinal aerodynamic performance of tandem-wing UAV model was researched through wind tunnel experiment. Geometry variables were forward and rear wing spans, rear wing dihedral angle and longitudinal stagger. Lift, drag and longitudinal moment coefficients were defined.The possibility of lift-to-drag ratio increasing at cruise regime was proofed. Rear wing negative dihedral angle application is able to increase maximal lift-to-drag ratio by more than 1.0 or about 10 %.It was found that wing dihedral angle effectiveness depends from relation of forward and rear wing spans and from longitudinal stagger. Longitudinal stagger increasing results in dihedral angle effectiveness falling if forward wing span is higher than rear wing. For bigger rear wing span increasing of longitudinal stagger results in dihedral angle effectiveness gaining. The hypothesis was declared that proposes theoretical explanation of experimentally founded dependencies.Also dihedral angle appearance increases lift slope because of rear wing carrying capacity gain and has almost no influence on maximal lift coefficient.All dependencies founded for rear wing negative dihedral angle are correct for forward wing positive dihedral angle except the last one is increasing longitudinal and lateral stability.

CFD analysis of variable geometric angle winglets

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ali Hussain Kazim ◽  
Abdullah Hamid Malik ◽  
Hammad Ali ◽  
Muhammad Usman Raza ◽  
Awais Ahmad Khan ◽  
...  
Keyword(s):  
Aerodynamic Performance ◽  
Sweep Angle ◽  
Content Type ◽  
Wing Model ◽  
Induced Drag ◽  
Computational Fluid Dynamics Analysis ◽  
Attached Flow ◽  
Drag Ratio ◽  
Fuel Costs ◽  
Lift To Drag Ratio

Purpose Winglets play a major role in saving fuel costs because they reduce the lift-induced drag formed at the wingtips. The purpose of this paper is to obtain the best orientation of the winglet for the Office National d’Etudes et de Recherches Aérospatiales (ONERA) M6 wing at Mach number 0.84 in terms of lift to drag ratio. Design/methodology/approach A computational fluid dynamics analysis of the wing-winglet configuration based on the ONERA M6 airfoil on drag reduction for different attack angles at Mach 0.84 was performed using analysis of systems Fluent. First, the best values of cant and sweep angles in terms of aerodynamic performance were selected by performing simulations. The analysis included cant angle values of 30°, 40°, 45°, 55°, 60°, 70° and 75°, while for the sweep angles 35°, 45°, 55°, 65° and 75° angles were used. The aerodynamic performance was measured in terms of the obtained lift to drag ratios. Findings The results showed that slight alternations in the winglet configuration can improve aerodynamic performance for various attack angles. The best lift to drag ratio for the winglet was achieved at a cant angle of 30° and a sweep angle of 65°, which caused a 5.33% increase in the lift to drag ratio. The toe-out angle winglets as compared to the toe-in angles caused the lift to drag ratio to increase because of more attached flow at its surface. The maximum value of the lift to drag ratio was obtained with a toe-out angle (−5°) at an angle of attack 3° which was 2.53% greater than the zero-toed angle winglet. Originality/value This work is relatively unique because the cant, sweep and toe angles were analyzed altogether and led to a significant reduction in drag as compared to wing without winglet. The wing model was compared with the results provided by National Aeronautics and Space Administration so this validated the simulation for different wing-winglet configurations.

scholarly journals Shock Reduction through Opposing Jets—Aerodynamic Performance and Flight Stability Perspectives

2019 ◽  
Vol 10 (1) ◽  
pp. 180 ◽  
Author(s):  
Shagufta Rashid ◽  
Fahad Nawaz ◽  
Adnan Maqsood ◽  
Rizwan Riaz ◽  
Shuaib Salamat
Keyword(s):  
Pressure Ratio ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Flight Stability ◽  
Supersonic Regime ◽  
Free Stream Mach Number ◽  
Drag Ratio ◽  
First Time ◽  
Lift To Drag Ratio

In this research paper, investigations of counter flow (opposing) jet on the aerodynamic performance, and flight stability characteristics of an airfoil with blunt leading-edge in supersonic regime are performed. Unsteady Reynolds-Averaged Navier-Stokes ( U R A N S ) based solver is used to model the flow field. The effect of angle of attack ( α ), free-stream Mach number ( M ∞ ), and pressure ratio ( P R ) on aerodynamic performance of airfoil with and without jet are compared. The results indicate that the opposing jet reduces drag from 30 % to 70 % , improves the maximum lift-to-drag ratio from 2.5 to 4.0, and increases shock stand-off distance from 15 % to 35 % depending on flow conditions. The effect of opposing jet on longitudinal flight stability characteristics, studied for the first time, indicate improvement in dynamic stability coefficients ( C m q + C m α ˙ ) at low angles of attack. It is concluded that the opposing jet can help mitigate flight disturbances in supersonic regime.

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