Comparison between Methods of Generation of Waveriders Derived from Streamline Tracing and Simplified Method

2013 ◽  
Vol 390 ◽  
pp. 134-140
Author(s):  
Feng Ding ◽  
Jun Liu ◽  
Liang Jin ◽  
Shi Bin Luo
Keyword(s):  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
High Lift ◽  
Shape Factors ◽  
Simplified Method ◽  
Streamline Tracing ◽  
Simulation Results ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Tracing Method

Waverider with a high lift-to-drag ratio has drawn an ever increasing attention. Usually, waverider is obtained by tracing streamline. A simplified generation method of waverider is introduced in the present paper named geometric relations method. Three groups of cone-derived waverider configuration, respectively, based on the geometric relations method and the streamline tracing method are generated for the comparisons of the shape factors, inviscid aerodynamic characteristics, and flow field structures by investigating the numerical simulation results. The results show that the effect of the Mach number and the shock angle on the differences caused by the two methods are not significantly different. While the volumetric efficiency of the waverider configuration based on the geometric relations method is larger than those based on the streamline tracing, the inviscid lift-to-drag ratio of the former is less than the latter. Although the geometric relations method is much easier than the streamline tracing method, the simplified method reduces the aerodynamic performance of the waverider configuration.

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.

420 Aerodynamic Characteristics and Flow Field of High Lift-to-drag Ratio Airfoils in Low Reynolds Number

2015 ◽  
Vol 2015.68 (0) ◽  
pp. 167-168 ◽  
Author(s):  
Takahiro MAKIZONO ◽  
Gaku SASAKI ◽  
Hiroshi OCHI ◽  
Takaaki MATSUMOTO ◽  
Koichi YONEMOTO
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Low Reynolds Number ◽  
Aerodynamic Characteristics ◽  
High Lift ◽  
Low Reynolds ◽  
Drag Ratio ◽  
Lift To Drag Ratio

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.

Effects of Aspect Ratio on the Hydrodynamic Performance of Circular Cambered Otter Board

2018 ◽  
Author(s):  
Liuyi Huang ◽  
Yuyan Li ◽  
Jiqiang Xu ◽  
Qingchang Xu ◽  
Fenfang Zhao ◽  
...  
Keyword(s):  
Lift Coefficient ◽  
Flow Distribution ◽  
Full Scale ◽  
Hydrodynamic Performance ◽  
High Lift ◽  
Aspect Ratios ◽  
Simulation Results ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Good Agreement

An otter board is an important device that provides a desired horizontal opening of a trawl net. A high lift coefficient or lift-to-drag ratio is required for an otter board to maintain fishing efficiency. In the present work, the hydrodynamic performance of a circular cambered otter board was studied by numerical simulation, including the effects of aspect ratios (AR), and flow distribution around the otter board. Model tests were conducted in the flume tank as well as a comparison to the numerical results. It showed that simulation results exhibited very good agreement with experiment results. Results demonstrated that the model otter board had a critical angle of attack (AOA) of 50° (when the stall appeared). The maximum lift coefficient and lift-to-drag ratio of the model otter board were 2.421 and 3.719, respectively. However, the maximum values of the full-scale otter board increased first and then decreased with an increasing AR. And the full-scale otter board had a better performance when AR = 2.489, it can enhance the lift coefficient by 17.4% compared with the initial otter board (AR = 1.25). In addition, the flow distribution around the otter board showed that the flow was smooth at small AOAs, when it attacked at large AOA (exceeded 55°), flow separation and eddies were appeared at the lee-side of the otter board.

The adverse cyclic and collective pitch effect in a rotor

2019 ◽  
Vol 123 (1264) ◽  
pp. 805-827 ◽  
Author(s):  
Hak Yoon Kim
Keyword(s):  
Simulation Method ◽  
Navier Stokes ◽  
Equilibrium Conditions ◽  
High Lift ◽  
Helicopter Control ◽  
Shaft Angle ◽  
Simulation Results ◽  
Advance Ratio ◽  
Drag Ratio ◽  
Lift To Drag Ratio

AbstractNumerical simulations have been carried out for a 32.16-ft-diameter rotor in autorotational forward flight. Coupled flapping and rotational equations were solved using the transient simulation method (TSM) to ascertain the quasistatic torque equilibrium conditions. The Pitt/Peters inflow theory was adopted in the simulations, and an airfoil look-up table made by a compressible Navier-Stokes solver was used. The adverse cyclic and collective pitch inputs were introduced in a similar fashion to helicopter control in that the cyclic lever is pulled back and the collective lever is pushed down for increasing airspeeds. The simulation results showed that the longitudinal cyclic pitch input combined with a lowered collective pitch increases the rotating torque for a low shaft angle and an advance ratio greater than one, producing both high lift and a high lift-to-drag ratio. Upon introducing the adverse cyclic and collective pitch inputs, the control range broadened, and a torque equilibrium condition was detected at 414.7kt (700ft/s) of airspeed in the simulation.

Aerodynamic Performance of Blended Wing Body Aircraft with Distributed Propulsion

2014 ◽  
Vol 1016 ◽  
pp. 354-358 ◽  
Author(s):  
Wan Fang Yan ◽  
Jiang Hao Wu ◽  
Yan Lai Zhang
Keyword(s):  
Lift Coefficient ◽  
Large Angle ◽  
Aerodynamic Performance ◽  
Propulsion System ◽  
System Configuration ◽  
High Lift ◽  
Distributed Propulsion ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Center Body

A 350-passenger BWB with a distributed propulsion system configuration is carried out and its aerodynamic performance in cruising and taking off are analyzed and discussed. It is shown from computation that the integrated configuration has a commendable aerodynamic performance in cruising and taking off. The cruise lift to drag ratio is reach to 24.0 in cruising. The ingestion effect of the propulsion system leads to a high lift at a low speed. The maximum lift coefficient CLmax is 1.62 when α=20° in taking off. In addition, the ingestion also delays the flow separation on the upper surface of center body, which contributes to a well stall performance of the configuration at large angle of attack.

scholarly journals Numerical Simulation of Flow over Bionic Airfoil

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Lishu Hao ◽  
Yongwei Gao ◽  
Binbin Wei ◽  
Ke Song
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Curve Shape ◽  
Effective Angle ◽  
Trailing Edge Flap ◽  
Cfd Method ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Bionic Airfoil

In this study, the aerodynamic performance of bionic airfoil was numerically studied by CFD method. The bionic airfoil was represented by the combination of airfoil and a small trailing edge flap. A variety of configurations were calculated to study the effect of flap parameters, such as the flap angle, position, and shape, on the bionic airfoil aerodynamic characteristics based on two layouts which were that (1) there was a tiny gap between the airfoil and the flap and (2) there was no gap between the two. The results showed that the flap angle and position had significant effects on the aerodynamic performance of the airfoil with the two layouts. Compared with the clean airfoil, the maximum lift coefficients of the first layout and the second layout could be increased by 10.9% and 7.9%, respectively. And the effective angle of attack (AoA) range for improving the lift-to-drag ratio could reach 7°. The flap shape also affected the airfoil aerodynamic characteristics, and the flap with the sinusoid curve shape showed ideal performance.

Aerodynamic performance improvement of a canard control missile

2017 ◽  
Vol 89 (6) ◽  
pp. 871-878 ◽  
Author(s):  
M. Tahani ◽  
M. Masdari ◽  
M. Kazemi
Keyword(s):  
Aspect Ratio ◽  
Drag Coefficient ◽  
Cross Section ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Slender Body Theory ◽  
Content Type ◽  
Drag Ratio ◽  
Body Theory ◽  
Lift To Drag Ratio

Purpose This paper aims to analyze the influence of the changings in geometrical parameters on the aerodynamic performance of the control canard projectiles. Design/methodology/approach Because of the mentioned point, the range of projectiles increment has a considerable importance, and the design algorithm of a control canard projectile was first written. Then, were studied the effects of canard geometric parameters such as aspect ratio, taper ratio and deflectable nose on lift to drag coefficient ratio, static margin based on the slender body theory and cross section flow. Findings The code results show that aspect ratio increment, results in an increase in lift-to-drag ratio of the missile, but increase in canard taper ratio results in increasing of lift-to-drag ratio at 1° angle of attack, while during increasing the canard taper ratio up to 0.67 at 4° angle of attack, lift to drag first reaches to maximum and then decreases. Also, static margin decreases with canard taper ratio and aspect ratio increment. The developed results for this type of missile were compared with same experimental and computational fluid dynamic (CFD) results and appreciated agreement with other results at angles of attack between 0° and 6°. Practical implications To design a control canard missile, the effect of each geometric parameter of canard needs to be estimated. For this purpose, the suitable algorithm is used. In this paper, the effects of canard geometric parameters, such as aspect ratio, taper ratio and deflectable nose on lift-to-drag coefficient ratio and static margin, were studied with help of the slender body theory and cross-section flow. Originality/value The contribution of this paper is to predict the aerodynamic characteristics for the control canard missile. In this study, the effect of the design parameter on aerodynamic characteristics can be estimated, and the effect of geometrical characteristics has been analyzed with a suitable algorithm. Also, the best lift-to-drag coefficient for the NASA Tandem Control Missile at Mach 1.75 was selected at various angles of attack. The developed results for this type of missile were compared with same experimental and CFD results.

scholarly journals A Parametric Study of Trailing Edge Flap Implementation on Three Different Airfoils Through an Artificial Neuronal Network

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 828
Author(s):  
Igor Rodriguez-Eguia ◽  
Iñigo Errasti ◽  
Unai Fernandez-Gamiz ◽  
Jesús María Blanco ◽  
Ekaitz Zulueta ◽  
...  
Keyword(s):  
Aerodynamic Coefficients ◽  
Trailing Edge ◽  
High Lift ◽  
Trailing Edge Flaps ◽  
Artificial Neural Network Ann ◽  
Lift And Drag ◽  
Artificial Neuronal Network ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Trailing edge flaps (TEFs) are high-lift devices that generate changes in the lift and drag coefficients of an airfoil. A large number of 2D simulations are performed in this study, in order to measure these changes in aerodynamic coefficients and to analyze them for a given Reynolds number. Three different airfoils, namely NACA 0012, NACA 64(3)-618, and S810, are studied in relation to three combinations of the following parameters: angle of attack, flap angle (deflection), and flaplength. Results are in concordance with the aerodynamic results expected when studying a TEF on an airfoil, showing the effect exerted by the three parameters on both aerodynamic coefficients lift and drag. Depending on whether the airfoil flap is deployed on either the pressure zone or the suction zone, the lift-to-drag ratio, CL/CD, will increase or decrease, respectively. Besides, the use of a larger flap length will increase the higher values and decrease the lower values of the CL/CD ratio. In addition, an artificial neural network (ANN) based prediction model for aerodynamic forces was built through the results obtained from the research.

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