Numerical study of geometric morphing wings of the 1303 UCAV

2021 ◽  
pp. 1-17
Author(s):  
B. Nugroho ◽  
J. Brett ◽  
B.T. Bleckly ◽  
R.C. Chin
Keyword(s):  
Flight Control ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Morphing Wing ◽  
Rolling Moment ◽  
Wide Range ◽  
Morphing Wings ◽  
Wing Geometry ◽  
Lift And Drag ◽  
Wing Morphing

ABSTRACT Unmanned Combat Aerial Vehicles (UCAVs) are believed by many to be the future of aerial strike/reconnaissance capability. This belief led to the design of the UCAV 1303 by Boeing Phantom Works and the US Airforce Lab in the late 1990s. Because UCAV 1303 is expected to take on a wide range of mission roles that are risky for human pilots, it needs to be highly adaptable. Geometric morphing can provide such adaptability and allow the UCAV 1303 to optimise its physical feature mid-flight to increase the lift-to-drag ratio, manoeuvrability, cruise distance, flight control, etc. This capability is extremely beneficial since it will enable the UCAV to reconcile conflicting mission requirements (e.g. loiter and dash within the same mission). In this study, we conduct several modifications to the wing geometry of UCAV 1303 via Computational Fluid Dynamics (CFD) to analyse its aerodynamic characteristics produced by a range of different wing geometric morphs. Here we look into two specific geometric morphing wings: linear twists on one of the wings and linear twists at both wings (wash-in and washout). A baseline CFD of the UCAV 1303 without any wing morphing is validated against published wind tunnel data, before proceeding to simulate morphing wing configurations. The results show that geometric morphing wing influences the UCAV-1303 aerodynamic characteristics significantly, improving the coefficient of lift and drag, pitching moment and rolling moment.

Pitching Dynamic Response of Variable Sweep Wing Aircraft

2012 ◽  
Vol 197 ◽  
pp. 159-163 ◽  
Author(s):  
Lai Bin Xu ◽  
Shu Xing Yang ◽  
Bo Mo
Keyword(s):  
Dynamic Response ◽  
Flight Control ◽  
Equations Of Motion ◽  
Center Of Gravity ◽  
Moment Of Inertia ◽  
Morphing Wing ◽  
Wing Morphing

The dynamic response of Variable Sweep Wing Aircraft (VSWA) with the wing sweeping is presented. The center of gravity (cg) of the aircraft, location of each wing partition , and moment of inertia alter significantly due to the wing morphing, resulting in considerably change of the dynamics of the aircraft. The extended equations of motion (EOMs) suitable for morphing wing aircraft are derived. Compared with the traditional EOMs, there are 4 additional forces and moments exhibiting in the extended EOMs due to the wing morphing. The results show that the additional forces and moments can affect the flight control considerably.

scholarly journals Aerodynamic characteristics of a feathered dinosaur measured using physical models. Effects of form on static stability and control effectiveness.

2013 ◽  
Author(s):  
Dennis Evangelista ◽  
Griselda Cardona ◽  
Eric Guenther-Gleason ◽  
Tony Huynh ◽  
Austin Kwong ◽  
...  
Keyword(s):  
Flight Control ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Physical Models ◽  
Stability And Control ◽  
Control Effectiveness ◽  
Biomechanical Constraints ◽  
Lift And Drag ◽  
And Control

We report the effects of posture and morphology on the static aerodynamic stability and control effectiveness of physical models based on the feathered dinosaur,Microraptor gui, from the Cretaceous of China. Postures had similar lift and drag coefficients and were broadly similar when simplified metrics of gliding were considered, but they exhibited different stability characteristics depending on the position of the legs and the presence of feathers on the legs and the tail. Both stability and the function of appendages in generating maneuvering forces and torques changed as the glide angle or angle of attack were changed. These are significant because they represent an aerial environment that may have shifted during the evolution of directed aerial descent and other aerial behaviors. Certain movements were particularly effective (symmetric movements of the wings and tail in pitch, asymmetric wing movements, some tail movements). Other appendages altered their function from creating yaws at high angle of attack to rolls at low angle of attack, or reversed their function entirely. WhileM. guilived afterArchaeopteryxand likely represents a side experiment with feathered morphology, the general patterns of stability and control effectiveness suggested from the manipulations of forelimb, hindlimb and tail morphology here may help understand the evolution of flight control aerodynamics in vertebrates. Though these results rest on a single specimen, as further fossils with different morphologies tested, the findings here could be applied in a phylogenetic context to reveal biomechanical constraints on extinct flyers arising from the need to maneuver. Now published in PLOS ONE http://dx.plos.org/10.1371/journal.pone.0085203

A Parametric Numerical Study of the Effects of Inlet Swirl Distortion on a Transonic Compressor Stage

2013 ◽  
Author(s):  
Taieb Ben Sghaier ◽  
Ahad Mehdi ◽  
Vassilios Pachidis ◽  
David MacManus
Keyword(s):  
Numerical Study ◽  
Pressure Ratio ◽  
Underlying Mechanism ◽  
Aerodynamic Characteristics ◽  
Vortical Flow ◽  
Compressor Stage ◽  
Significant Drop ◽  
Transonic Compressor ◽  
Wide Range ◽  
Compressor Performance

The ingestion or manifestation of a vortical flow can have dramatic effects on an aero engine. It is therefore imperative to quantify these effects and understand their underlying mechanism. This numerical study analyses the response of a transonic compressor stage to the ingestion of different streamwise vortical distortions using steady-state CFD. The vortex is described using a number of features, which are varied and combined together in order to generate a wide range of different swirl disturbances. The initial aim of this research is to identify the vortex features which have the highest impact on compressor performance. A numerical model of a compressor stage is generated which enables prescribed vortical flows to be imposed at the domain inlet. The method is validated against experimental data which was obtained under clean, undistorted conditions. The response of the compressor following the ingestion of a vortex is assessed both in terms of overall compressor performance parameters as well as more detailed aerodynamic characteristics. The results show that the compressor is sensitive to the vortex magnitude, core size, polarity and radial location. Furthermore, co-rotating, high-strength vortices which are ingested in the near-hub region cause the most significant drop in pressure ratio and corrected mass flow. In contrast, counter-rotating vortices cause little change in compressor performance. Overall, the work shows that modest swirl distortions can have a notable impact on the compressor performance and stability, and highlights the growing need to develop methods and an understanding of how this class of distortion can be evaluated during the engine design phase.

Cross-Wind Influence on Low Aspect Ratio Wings at Low Reynolds Numbers

2013 ◽  
Author(s):  
Amir Karimi Noughabi ◽  
Mehran Tadjfar
Keyword(s):  
Aspect Ratio ◽  
Numerical Study ◽  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Reynolds Numbers ◽  
Aerodynamic Characteristics ◽  
Low Aspect Ratio ◽  
Aspect Ratios ◽  
Lift And Drag ◽  
Lift And Drag Coefficient

The aerodynamics of the low aspect ratio (LAR) wings is of outmost importance in the performance of the fixed-wing micro air vehicles (MAVs). The flow around these wings is widely influenced by three dimensional (3D) phenomena: including wing-tip vortices, formation of laminar bubble, flow separation and reattachment, laminar to turbulent transition or any combination of these phenomena. All the recent studies consider the aerodynamic characteristics of the LAR wings under the effect of the direct wind. Here we focus on the numerical study of the influence of cross-wind on flow over the inverse Zimmerman wings with the aspect ratios (AR) between 1 and 2 at Reynolds numbers between 6×104 and 105. We have considered cross-wind’s angles from 0° to 40° and angle of attack from 0° to 12°. The results show that lift and drag coefficient generally decrease when the angle of the cross-wind is increased.

scholarly journals Aerodynamic Characteristics of a Single Airfoil for Vertical Axis Wind Turbine Blades and Performance Prediction of Wind Turbines

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 257
Author(s):  
Samuel Mitchell ◽  
Iheanyichukwu Ogbonna ◽  
Konstantin Volkov
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Computational Cost ◽  
Aerodynamic Characteristics ◽  
Wind Turbine Blades ◽  
Aerodynamic Forces ◽  
Rans Model ◽  
Wide Range ◽  
Lift And Drag

The design of wind turbines requires a deep insight into their complex aerodynamics, such as dynamic stall of a single airfoil and flow vortices. The calculation of the aerodynamic forces on the wind turbine blade at different angles of attack (AOAs) is a fundamental task in the design of the blades. The accurate and efficient calculation of aerodynamic forces (lift and drag) and the prediction of stall of an airfoil are challenging tasks. Computational fluid dynamics (CFD) is able to provide a better understanding of complex flows induced by the rotation of wind turbine blades. A numerical simulation is carried out to determine the aerodynamic characteristics of a single airfoil in a wide range of conditions. Reynolds-averaged Navier–Stokes (RANS) equations and large-eddy simulation (LES) results of flow over a single NACA0012 airfoil are presented in a wide range of AOAs from low lift through stall. Due to the symmetrical nature of airfoils, and also to reduce computational cost, the RANS simulation is performed in the 2D domain. However, the 3D domain is used for the LES calculations with periodical boundary conditions in the spanwise direction. The results obtained are verified and validated against experimental and computational data from previous works. The comparisons of LES and RANS results demonstrate that the RANS model considerably overpredicts the lift and drag of the airfoil at post-stall AOAs because the RANS model is not able to reproduce vorticity diffusion and the formation of the vortex. LES calculations offer good agreement with the experimental measurements.

scholarly journals CFD Analysis of the Sideslip Angle Effect around a BWB Type Configuration

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Arim Ko ◽  
Kyoungsik Chang ◽  
Dong-Jin Sheen ◽  
Young-Hee Jo ◽  
Ho Joon Shim
Keyword(s):  
Skin Friction ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Sideslip Angle ◽  
Rolling Moment ◽  
Freestream Velocity ◽  
Highly Nonlinear ◽  
Grid Points ◽  
Lift And Drag

In this study, we conducted numerical simulations for a nonslender BWB type planform with a rounded leading edge and span of 2.0 m to analyze the effect of the sideslip angle on the planform at a freestream velocity of 60 m/s. The Reynolds number based on the mean chord length was 2.9×106, and we considered the angle of attack ranging from -4° to 16° and sideslip angles up to 20°. We used an unstructured mesh with a prism layer for the boundary layer with 1.11×107 grid points, and the k−ω SST turbulence model. We analyzed force and moment coefficients with respect to variation of angle of attack and sideslip angles. Side force and rolling/yawing moment coefficients had highly nonlinear relationships with the sideslip angle while lift and drag coefficients were not significantly affected. We interpreted the mechanism of these aerodynamic characteristics based on pressure and skin friction contours. Suction pressure near the leading edge had a marked effect on the pitching and rolling moment. We identified five flow types on the blunt leading edge swept wing by skin friction lines and off-body streamlines at a high angle of attack and sideslip angles.

scholarly journals Choosing the aerodynamic configuration of a subsonic cruise missile

2019 ◽  
Vol 18 (3) ◽  
pp. 59-66
Author(s):  
M. A. Kovalev ◽  
A. N. Nikitin
Keyword(s):  
Aerodynamic Characteristics ◽  
Cruise Missile ◽  
Swept Wing ◽  
Horizontal Flight ◽  
Wide Range ◽  
The Difference ◽  
Cruise Missiles ◽  
Lift And Drag ◽  
Aerodynamic Configuration ◽  
Aerodynamic Quality

The paper presents a comparison of two aerodynamic configurations of subsonic cruise missiles, characterized by the use of swept-back and forward-swept wings. The results of wind tunnel tests with the use of an automated measurement system characterizing the dependence of the lift and drag coefficients in a sufficiently wide range of angles of attack are presented. This allows us to compare the aerodynamic quality of the cruise missile models under investigation. The analysis of the results of experiments with the models and calculations in conditions of steady-state low-altitude horizontal flight revealed that the configurations of cruise missiles with a moderately swept wing, selected for comparison, have similar aerodynamic characteristics. Both configurations ensure the mode of flight at a given altitude and velocity in the range of the best angles of attack (maximum aerodynamic quality). Missiles with swept-back wings have better aerodynamic performance in terms of maximum aerodynamic quality, while the lift increment due to reduced trim losses for the forward-swept wing configuration only partially compensates the difference of the aerodynamic characteristics of the alternatives under consideration. Therefore, it is concluded that the choice of aerodynamic configuration of a subsonic cruise missile with a swept-back wing is preferable.

scholarly journals Adaptive Wing Morphing Strategy and Flight Control Method of a Morphing Aircraft Based on Reinforcement Learning

2019 ◽  
Vol 37 (4) ◽  
pp. 656-663
Author(s):  
Binbin Yan ◽  
Yong Li ◽  
Pei Dai ◽  
Muzeng Xing
Keyword(s):  
Reinforcement Learning ◽  
Flight Control ◽  
Control Method ◽  
Sliding Mode ◽  
Normal Load ◽  
Aerodynamic Characteristics ◽  
Morphing Aircraft ◽  
Adaptive Wing ◽  
Aerodynamic Parameters ◽  
Wing Morphing

The morphing aircraft can change different wing shapes or geometries to achieve the optimal flight performance according to various mission scenarios. In this paper, DATCOM is used to calculate aerodynamic parameters based on Firebee UAV morphing aircraft with different wing configurations and analyze aerodynamic characteristics. A novel adaptive wing morphing strategy for morphing aircraft based on reinforcement learning method is proposed. This method can highly meet the demand of keeping optimal performance in multiple flight conditions, and the adaptive wing morphing strategy, three-loop normal load altitude controller and sliding mode velocity controller can together make sure stability of morphing aircraft during morphing process with good tracking performance.

scholarly journals Investigation of a NACA0012 Finite Wing Aerodynamics at Low Reynold’s Numbers and 0º to 90º Angle of Attack

2019 ◽  
Author(s):  
Shahrooz Eftekhari ◽  
Abdulkareem Shafiq Mahdi Al-Obaidi
Keyword(s):  
Drag Force ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Poor Performance ◽  
Aerodynamic Characteristics ◽  
Airfoil Surface ◽  
Wing Geometry ◽  
Stall Angle ◽  
Finite Wing ◽  
Lift And Drag

The aerodynamic characteristics of a NACA0012 wing geometry at low Reynold’s numbers and angle of attack ranging from 0º to 90º are investigated using numerical simulations and the results are validated by wind tunnel experiments. Further experiments are conducted at low Reynold’s numbers of 1 × 105, 2 × 105 and 3 × 105. Findings of the study show a similar trend for the lift and drag coefficients at all the investigated Reynold’s numbers. The lift coefficient is linearly increased with angle of attack until it reaches its maximum value at 32º which is the stall angle. It is observed that further increment in angle of attack results in decrement of lift coefficient until it reaches its minimum value at 90º angle of attack. The drag force acting on the airfoil increases as the angle of attack is increased and increment in the drag force results in change of laminar flow to turbulent flow. As the turbulence gets higher the flow starts to separate from the airfoil surface due to eddies generated by turbulence. Hence, the lift force generated by the wing is reduced and drag force is increased simultaneously, which results in poor performance of the wing.

MANUFACTURING METHOD OF THE MORPHING WING STRUCTURE FOR UAV BY CFRP WITH APPLYING THE ELECTROFORMED RESIN MOLDING METHOD

2021 ◽  
Author(s):  
KAZUAKI KATAGIRI ◽  
CHOONG SIK PARK ◽  
SHIMPEI YAMAGUCHI ◽  
SONOMI KAWAKITA ◽  
KIM DAEKWI ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Flight Control ◽  
Lattice Structure ◽  
Polymer Particle ◽  
Morphing Wing ◽  
Aircraft Wing ◽  
Manufacturing Method ◽  
Morphing Wings ◽  
Wing Structure ◽  
Sufficient Strength

Aircraft flight control usually requires driving flaps and ailerons. However, the air drags increase significantly due to the corners of flaps and aileron. Especially, the gap between mother wing and flap / aileron causes a drag increase. Therefore, studies are being conducted on morphing wings that smoothly and greatly deform the wing surface. For aircraft wing, it is needless to say that strength is important to sustain lift and drag for the aircraft during the flight. For morphing wings, in addition, actuators must be mounted inside the wing to enable the morphing deformation. Moreover, for the aircraft wing, weight is quite important. Therefore, carbon fiber reinforced plastic (CFRP) is currently most suitable for aircraft wing structural materials. However, it is difficult to mold CFRP so that it has sufficient strength and can be morphed. In this study, by using CFRP, the morphing wing structure was prototyped with targeting a small unmanned aerial vehicle (UAV) weighing 3 kg. The CFRP lattice structure that enables morphing deformation was designed and manufactured by applying the electrodeposition resin molding (ERM) method which was developed by the authors. In the ERM method, firstly, the carbon fiber was fixed with a jig according to the designed morphing wing structure, and immersed in the electrodeposition solution. Secondly, the epoxy polymer particle in the solution were electrophoresed and impregnated between carbon fibers. After thermal curing, the morphing wing structure was fabricated. Further, the loading-unloading torsion and bending tests of the morphing wing structure were carried out. Smooth morphing deformation and sufficient strength were confirmed.

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