scholarly journals A New Aerodynamic Optimization Method with the Consideration of Dynamic Stability

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mi Baigang ◽  
Wang Xiangyu
Keyword(s):  
Dynamic Stability ◽  
Optimization Design ◽  
Optimization Method ◽  
Aerodynamic Optimization ◽  
Conventional Optimization ◽  
And Control ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Oscillation Method ◽  
Small Amplitude Oscillation

Dynamic stability is significantly important for flying quality evaluation and control system design of the advanced aircraft, and it should be considered in the initial aerodynamic design process. However, most of the conventional aerodynamic optimizations only focus on static performances and the dynamic motion has never been included. In this study, a new optimization method considering both dynamic stability and general lift-to-drag ratio performance has been developed. First, the longitudinal combined dynamic derivative based on the small amplitude oscillation method is calculated. Then, combined with the PSO (particle swarm optimization) algorithm, a dynamic stability derivative that must not be decreased is added to the constraints of optimization and the lift-drag ratio is chosen as the optimization objective. Finally, a new aerodynamic optimization method can be built. We take NACA0012 as an example to validate this method. The results show that the dynamic derivative calculation method is effective and conventional optimization design can significantly improve the lift-drag ratio. However, the dynamic stability is enormously changed at the same time. By contrast, the new optimization method can improve the lift-drag performance while maintaining the dynamic stability.

scholarly journals Fluid–structure interaction simulation on flight performance of a dragonfly wing under different pterostigma weights

2021 ◽  
Vol 37 ◽  
pp. 216-229
Author(s):  
Yung Jeh Chu ◽  
Poo Balan Ganesan ◽  
Mohamad Azlin Ali
Keyword(s):  
Optimization Design ◽  
Fluid Structure Interaction ◽  
Spatial Location ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Dragonfly Wing ◽  
Interaction Simulation ◽  
Wing Performance ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract The dragonfly wings provide insights for designing an efficient biomimetic micro air vehicle (BMAV). In this regard, this study focuses on investigating the effect of the pterostigma weight loading and its spatial location on the forewings of dragonfly by using the fluid–structure interaction simulation. This study also investigates the effect of change in the wing elasticity and density on the wing performance. The forewing, which mimics the real dragonfly wing, is flat with a 47.5 mm span and a 0.4 mm thickness. The wing was set to cruise at 3 m/s with a constant flapping motion at a frequency of 25 Hz. This study shows that a small increase of pterostigma loading (11% of wing weight) at the tip of the wing significantly improves the lift to drag ratio, CL/CD, which has 129.16% increment in comparison with no loading. The lift to drag ratio depends on the pterostigma location, pterostigma loading, elastic modulus and density. The results of this study can be used as a reference in future BMAV wing optimization design.

Aerodynamic Optimization Design of Airfoil Shape Using Entropy Generation as an Objective

2018 ◽  
Vol 11 (2) ◽  
Author(s):  
Wei Wang ◽  
Jun Wang ◽  
Xiao-Pei Yang ◽  
Yan-Yan Ding
Keyword(s):  
Entropy Generation ◽  
Energy Cost ◽  
Optimization Design ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Aerodynamic Optimization ◽  
Analysis And Design ◽  
Constraint Model ◽  
The Impact ◽  
Drag Ratio

Abstract An entropy analysis and design optimization methodology is combined with airfoil shape optimization to demonstrate the impact of entropy generation on aerodynamics designs. In the work herein, the entropy generation rate is presented as an extra design objective along with lift-drag ratio, while the lift coefficient is the constraint. Model equation, which calculates the local entropy generation rate in turbulent flows, is derived by extending the Reynolds-averaging of entropy balance equation. The class-shape function transform (CST) parametric method is used to model the airfoil configuration and combine the radial basis functions (RBFs) based mesh deformation technique with flow solver to compute the quantities such as lift-drag ratio and entropy generation at the design condition. From the multi-objective solutions which represent the best trade-offs between the design objectives, one can select a set of airfoil shapes with a low relative energy cost and with improved aerodynamic performance. It can be concluded that the methodology of entropy generation analysis is an effective tool in the aerodynamic optimization design of airfoil shape with the capability of determining the amount of energy cost.

scholarly journals Optimal Skip Entry Trajectory for Lunar Return Vehicle with Trim-Flaps

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Yin Wang ◽  
Keming Yao
Keyword(s):  
Trajectory Optimization ◽  
Optimization Design ◽  
Lift Coefficient ◽  
Heat Rate ◽  
State Constraint ◽  
Skip Entry ◽  
Drag Ratio ◽  
Minimum Heat ◽  
Lift To Drag Ratio ◽  
Order State

A medium lift-to-drag ratio lunar return vehicle with trim-flaps is presented in this paper. The trajectory optimization design under heat-rate constrain for skip entry lunar return vehicle is analyzed. The optimization problem with a first-order state constraint is introduced. The trajectory applying the Pontryagin maximum principle under the performance of minimum heat is optimized, and the optimal expression of lift coefficient is derived. The simulation studies show that this research method can decrease the heat-rate effectively.

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.

scholarly journals Conceptual Design, Flying, and Handling Qualities Assessment of a Blended Wing Body (BWB) Aircraft by Using an Engineering Flight Simulator

Aerospace ◽  
2020 ◽  
Vol 7 (5) ◽  
pp. 51 ◽  
Author(s):  
Clayton Humphreys-Jennings ◽  
Ilias Lappas ◽  
Dragos Mihai Sovar
Keyword(s):  
Static Stability ◽  
Flight Simulator ◽  
Handling Qualities ◽  
Stability And Control ◽  
Flying Qualities ◽  
Blended Wing Body ◽  
And Control ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Mission Profile

The Blended Wing Body (BWB) configuration is considered to have the potential of providing significant advantages when compared to conventional aircraft designs. At the same time, numerous studies have reported that technical challenges exist in many areas of its design, including stability and control. This study aims to create a novel BWB design to test its flying and handling qualities using an engineering flight simulator and as such, to identify potential design solutions which will enhance its controllability and manoeuvrability characteristics. This aircraft is aimed toward the commercial sector with a range of 3000 nautical miles, carrying 200 passengers. The BWB design was flight tested at an engineering flight simulator to first determine its static stability through a standard commercial mission profile, and then to determine its dynamic stability characteristics through standard dynamic modes. Its flying qualities suggested its stability with a static margin of 8.652% of the mean aerodynamic chord (MAC) and consistent response from the pilot input. In addition, the aircraft achieved a maximum lift-to-drag ratio of 28.1; a maximum range of 4,581 nautical miles; zero-lift drag of 0.005; while meeting all the requirements of the dynamic modes.

scholarly journals Aerodynamic Optimization of an Over-the-Wing-Nacelle-Mount Configuration

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Daisuke Sasaki ◽  
Kazuhiro Nakahashi
Keyword(s):  
Interference Effect ◽  
Jet Engines ◽  
Aerodynamic Design ◽  
Aerodynamic Optimization ◽  
High Lift ◽  
Aerodynamic Efficiency ◽  
Wing Geometry ◽  
Aerodynamic Interference ◽  
Drag Ratio ◽  
Lift To Drag Ratio

An over-the-wing-nacelle-mount airplane configuration is known to prevent the noise propagation from jet engines toward ground. However, the configuration is assumed to have low aerodynamic efficiency due to the aerodynamic interference effect between a wing and a nacelle. In this paper, aerodynamic design optimization is conducted to improve aerodynamic efficiency to be equivalent to conventional under-the-wing-nacelle-mount configuration. The nacelle and wing geometry are modified to achieve high lift-to-drag ratio, and the optimal geometry is compared with a conventional configuration. Pylon shape is also modified to reduce aerodynamic interference effect. The final wing-fuselage-nacelle model is compared with the DLR F6 model to discuss the potential of Over-the-Wing-Nacelle-Mount geometry for an environmental-friendly future aircraft.

scholarly journals Study on Multi-Objective Optimization Design and Passive Control of Wind Turbine Airfoil

2019 ◽  
Author(s):  
Yong Peng ◽  
Jun Wang ◽  
Wei Wang ◽  
Guoqing Yin
Keyword(s):  
Optimization Design ◽  
Passive Control ◽  
Lift Coefficient ◽  
Multi Objective Optimization ◽  
Trailing Edge ◽  
Multi Objective ◽  
Blunt Trailing Edge ◽  
Trade Offs ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract. In this paper, the class-shape function transform (CST) parametric method is used to parameterize the airfoil configuration, and a new airfoil is randomly generated within a limited range. The 2D Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) solver is used to compute the quantities such as lift-to-drag ratio. The multi-objective genetic algorithm performs multi-objective optimization design on the airfoil plane shape to achieve high lift-to-drag ratio with low drag in operating ranges of angle of attack, and finally obtains the Pareto optimal solution set. The mixed function of index method is used to increase the thickness of the trailing edge of the airfoil. From the multi-objective solutions and blunt trailing edge solutions which represent the best trade-offs between the design objectives, one can select a set of airfoil shapes with a low relative drag force and with improved aerodynamic performance. Taking a typical airfoil NACA4418 as an example. The results show that the optimized airfoil has a better pressure distribution than the original airfoil, effectively increasing the lift coefficient and reducing the drag coefficient. After thickening the trailing edge of the optimized airfoil, the results show that the lift coefficient is improved at all angles of attack and the stall is delayed. And the blunt trailing edge airfoil has better lift-to-drag characteristics than the original airfoil and the optimized airfoil.

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