scholarly journals Center Body Airfoil Design for Blended Wing Body Configuration

2018 ◽  
Vol 36 (2) ◽  
pp. 203-210
Author(s):  
Peifeng Li ◽  
Binqian Zhang ◽  
Yujin Tao ◽  
Zhenli Chen ◽  
Dong Li
Keyword(s):  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Positive Zero ◽  
Pitching Moment ◽  
Trailing Edge ◽  
Edge Loading ◽  
Blended Wing Body ◽  
Drag Ratio ◽  
Center Body

To design the center-body airfoil of a blended wing body configuration, the aerodynamic effects of the symmetrical airfoil, trailing-edge reflexed airfoil, leading-edge loaded airfoil and leading-edge loaded plus trailing-edge reflexed airfoil are investigated based on the constraints of system arrangement. A 150-passenger BWB configuration is studied; for a center-body with symmetrical airfoil, the larger outer-wing geometrical twist should be used to fulfill the positive zero-lift pitching moment according to the design requirements of longitudinal static stability, however, lift to drag ratio shows a big decrease. For leading-edge loaded airfoil, it is difficult to achieve a positive zero-lift pitching moment because of the platform limitation. For trailing-edge reflexed airfoil or leading-edge loaded plus trailing-edge reflexed airfoil, it is easy to achieve ideal design results when reasonably designing the leading-edge loading and trailing-edge unloading. The application of a blended wing body UAV shows that the loss of aerodynamic characteristics is small when adopting the "eagle hook" stealth leading edge that has the characteristics of leading edge loading.

scholarly journals Aerodynamic Analysis of Blended Wing Body - Unmanned Aerial Vehicle (BWB-UAV) Equipped with Horizontal Stabilizers

2019 ◽  
Vol 256 ◽  
pp. 02004
Author(s):  
Nornashiha Mohd Saad ◽  
Wirachman Wisnoe ◽  
Rizal Effendy Mohd Nasir ◽  
Zurriati Mohd Ali ◽  
Ehan Sabah Shukri Askari
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Cfd Simulation ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Flight Test ◽  
Longitudinal Direction ◽  
Static Stability ◽  
Pitching Moment ◽  
Aerial Vehicle ◽  
Blended Wing Body

This paper presents an aerodynamic characteristic study in longitudinal direction of UiTM Blended Wing Body-Unmanned Aerial Vehicle Prototype (BWB-UAV Prototype) equipped with horizontal stabilizers. Flight tests have been conducted and as the result, BWB experienced overturning condition at certain angle of attack. Horizontal stabilizer was added at different location and size to overcome the issue during the flight test. Therefore, Computational Fluid Dynamics (CFD) analysis is performed at different configuration of horizontal stabilizer using Spalart - Allmaras as a turbulence model. CFD simulation of the aircraft is conducted at Mach number 0.06 or v = 20 m/s at various angle of attack, α. The data of lift coefficient (CL), drag coefficient (CD), and pitching moment coefficient (CM) is obtained from the simulations. The data is represented in curves against angle of attack to measure the performance of BWB prototype with horizontal stabilizer. From the simulation, configuration with far distance and large horizontal stabilizer gives steeper negative pitching moment slope indicating better static stability of the aircraft.

New combinational active control strategy for improving aerodynamic characteristics of airfoil and rotor

2019 ◽  
Vol 234 (4) ◽  
pp. 977-996
Author(s):  
Yi-yang Ma ◽  
Qi-jun Zhao ◽  
Guo-qing Zhao
Keyword(s):  
Flow Control ◽  
Control Strategy ◽  
Active Flow Control ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Synthetic Jet ◽  
Dynamic Stall ◽  
Trailing Edge ◽  
Trailing Edge Flap ◽  
Cfd Method

In order to improve the aerodynamic characteristics of rotor, a new active flow control strategy by combining a synthetic jet actuator and a variable droop leading-edge or a trailing-edge flap has been proposed. Their control effects are numerically investigated by computational fluid dynamics (CFD) method. The validated results indicate that variable droop leading-edge and synthetic jet can suppress the formation of dynamic stall vortex and delay flow separation over rotor airfoil. Compared with the baseline state, Cdmax and Cmmax are significantly reduced. Furthermore, parametric analyses on dynamic stall control of airfoil by the combinational method are conducted, and it indicates that the aerodynamic characteristics of the oscillating rotor airfoil can be significantly improved when the non-dimensional frequency ( k*) of variable droop leading-edge is about 1.0. At last, simulations are conducted for the flow control of rotor by the combinational method. The numerical results indicate that large droop angle of variable droop leading-edge can better reduce the torque coefficient of rotor and the trailing-edge flap has the capability of increasing the thrust of rotor. Also, the synthetic jet could further improve the aerodynamic characteristics of rotor.

Modification of the NACA 632-415 Leading Edge for Better Aerodynamic Performance

2002 ◽  
Vol 124 (4) ◽  
pp. 327-334 ◽  
Author(s):  
Christian Bak ◽  
Peter Fuglsang
Keyword(s):  
Wind Tunnel ◽  
Wind Turbines ◽  
Power Level ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Dynamic Stall ◽  
Wind Tunnel Tests ◽  
Damping Characteristics ◽  
Edge Roughness ◽  
Drag Ratio

Double stall causes more than one power level when stall-regulated wind turbines operate in stall. This involves significant uncertainty on power production and loads. To avoid double stall, a new leading edge was designed for the NACA 632-415 airfoil, an airfoil that is often used in the tip region of wind turbines. A numerical optimization tool incorporating XFOIL was used with a special formulation for the airfoil leading edge shape. The EllipSys2D CFD code was used to analyze the modified airfoil. In theory and in wind tunnel tests, the modified airfoil showed smooth and stable stall characteristics with no tendency to double stall. Also, both theory and wind tunnel tests showed that the overall aerodynamic characteristics were similar to NACA 632-415 except for an increase in the lift-drag ratio below maximum lift and an increase in maximum lift. The wind tunnel tests showed that dynamic stall and aerodynamic damping characteristics for the modified airfoil and the NACA 632-415 airfoil were the same. The modified airfoil with leading edge roughness in general had better characteristics compared with the NACA 632-415 airfoil.

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.

Experimental Hydro- and Aerodynamics Research on Arrow

2014 ◽  
Vol 1022 ◽  
pp. 113-117
Author(s):  
Xiao An Long
Keyword(s):  
Wind Tunnel ◽  
Longitudinal Direction ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
The State ◽  
Water Tunnel ◽  
Theoretical Knowledge ◽  
Pitching Moment ◽  
Considerable Influence ◽  
Attached Flow

This study aims to investigate the hydro- and aerodynamic characteristics of arrows as understood within the field of archery and to contribute to theoretical knowledge, upon which archery techniques are based. The water tunnel and wind tunnel are used to test different arrows consisting of four famous brands.The results showed that when the angles of attack from -6°to 6°, the arrow remained in the state of attached flow. Arrows that had spiral plastic fletches demonstrated better states of flow than arrows with straight fletches. Within the range of the experimental angles of attack, the coefficients of lift increased, while the coefficients of pitching moment decreased when the angle of attack increased. The arrows showed static stability in the longitudinal direction. Arrow fetches also demonstrated considerable influence on the lift and pitching moment. The rolling of the arrows caused the change of the coefficient of lift. Based on the results, it can be concluded that arrow fetches are the major contributors to the arrows’ flight stability.

scholarly journals Aerodynamic Study of the NASA’s X-43A Hypersonic Aircraft

2020 ◽  
Vol 10 (22) ◽  
pp. 8211
Author(s):  
Àlex Navó ◽  
Josep M. Bergada
Keyword(s):  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Oblique Shock ◽  
Force Balance ◽  
Oblique Shock Wave ◽  
Vertical Force ◽  
Pitching Moment ◽  
Cfd Model ◽  
Hypersonic Aircraft

A 2D aerodynamic study of the NASA’s X-43A hypersonic aircraft is developed using two different approaches. The first one is analytical and based on the resolution of the oblique shock wave and Prandtl–Meyer expansion wave theories supported by an in-house program and considering a simplified aircraft’s design. The second approach involves the use of a Computational Fluid Dynamics (CFD) package, OpenFOAM and the real shape of the aircraft. The aerodynamic characteristics defined as the lift and drag coefficients, the aerodynamic efficiency and the pitching moment coefficient are calculated for different angles of attack. Evaluations are made for an incident Mach number of 7 and an altitude of 30 km. For both methodologies, the required angles of attack to achieve a Vertical Force Balance (VFB) and a completely zero pitching moment conditions are considered. In addition, an analysis to optimise the nose configuration of the aircraft is performed. The mass flow rate throughout the scramjet as a function of the angle of attack is also presented in the CFD model in addition to the pressure, density, temperature and Mach fields. Before presenting the corresponding results, a comparison between the aerodynamic coefficients in terms of the angle of attack of both models is carried out in order to properly validate the CFD model. The paper clarifies the requirements needed to make sure that both oblique shock waves originating from the leading edge meet just at the scramjet inlet clarifying the advantages of fulfilling such condition.

scholarly journals Research on Hydrodynamic Characteristics of Blended Wing Body Underwater Glider with Rudder

2020 ◽  
Vol 38 (1) ◽  
pp. 24-30
Author(s):  
Yunlong Ma ◽  
Guang Pan ◽  
Qiaogao Huang ◽  
Jinglu Li
Keyword(s):  
The Body ◽  
Hydrodynamic Characteristics ◽  
Shape Design ◽  
Underwater Glider ◽  
Trailing Edge ◽  
Blended Wing Body ◽  
The Difference ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Rudder Angle

In order to improve the maneuverability and stability of the Blended Wing Body (BWB) underwater glider, the trailing edge rudder is integrated into its shape design in this paper. Through the numerical simulation of CFD, the variation laws of the hydraulic parameters such as lift, drag, lift-to-drag ratio with the angle of attack and rudder angle are given. Compared with the traditional underwater glider, the BWB underwater glider not only has high loading capacity, but also has a maximum lift-to-drag ratio three times that of the former, resulting in higher energy efficiency. At the same time, by adding trailing edge rudders, the maneuverability of the BWB underwater glider is improved, and the lift-to-drag ratio under the same large rudder angle is increased by more than 30% compared with the variable-wing underwater glider. Finally, through the analysis of the numerical results and the cloud image, the difference interaction extent between the rudder and the body of the BWB underwater glider and the traditional torpedo or AUV is illustrated.

The Effect of Intake and Exhaust on the Two-Dimensional Airfoil in a Distributed Propulsion System

2016 ◽  
Author(s):  
Yongsheng Wang ◽  
Ming Zhou ◽  
Quanyong Xu
Keyword(s):  
Lift Coefficient ◽  
Leading Edge ◽  
Jet Flow ◽  
Propulsion System ◽  
Two Dimensional ◽  
Original Design ◽  
Trailing Edge ◽  
Distributed Propulsion ◽  
Drag Ratio

A new distributed propulsion system in which micro-engines were embedded into the wings was proposed. To consider the effects of the intake and exhaust of the engines, the system was simplified as a two-dimensional airfoil with a surface ingestion and a trailing edge jet. The influence of the layout was comprehensively studied with CFD. Compared to the original design, the surface ingestion and trailing edge jet can increase the lift coefficient. The lift-drag ratio increases at smaller attack angles (< 3°) and decreases at greater attack angles (> 3°). The lift-drag ratio improvement with surface ingestion at the leading edge is mainly due to the drop in drag, while the increase with ingestion close to the trailing edge is primarily because of the augment of lift. Moreover, increasing the temperature of the jet flow can enlarge the range of the attack angles with a higher lift-drag ratio.

The Effects on Wing Lift and Pitching Moment Due to the Fin of an Aircraft Flying at Supersonic Speeds

1967 ◽  
Vol 71 (674) ◽  
pp. 134-136
Author(s):  
L. B. Jones
Keyword(s):  
Supersonic Flow ◽  
Pressure Field ◽  
Free Stream ◽  
Leading Edge ◽  
Simple Expression ◽  
Pitching Moment ◽  
Trailing Edge ◽  
Blunt Trailing Edge ◽  
Sharp Edges

Summary:A simple expression is obtained for the lift induced upon a wing by the pressure field of the fin mounted upon the wing in supersonic flow. This expression holds for all fins with sharp edges provided that the wing trailing edge is normal to the free stream and that the Mach lines from the apex of the fin do not intersect the wing leading edge. If the fin has a blunt trailing edge the further restriction that the wing trailing edge is upstream of that of the fin is also required.Results for the induced lift and pitching moment are presented for a delta fin with variations in size and position of the fin relative to the wing trailing edge.

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