scholarly journals ОПТИМІЗАЦІЯ НОСОВОЇ ЧАСТИНИ ФЮЗЕЛЯЖУ З ТОЧКИ ЗОРУ АЕРОДИНАМІКИ ЛІТАКА

2020 ◽  
pp. 127-138
Author(s):  
Вячеслав Сергеевич Долгих
Keyword(s):  
Control Systems ◽  
Flight Control ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Cylindrical Part ◽  
Scale Model ◽  
Computational Grids ◽  
Cylinder Axis ◽  
Flow Acceleration ◽  
Acceleration Zone

The paper represents the analysis intended to optimize the fuselage nose section with regard to aircraft aerodynamics in the process of development of an unmanned transport aircraft (UTA). The article deals with provisions of high aerodynamic efficiency that cannot be achieved without proper selection of the shape and optimal fuselage parameters that determine mutual interference of aircraft components and units. When analyzing the flow improvement around the fuselage nose in flight, three fuselage versions were considered listed further: 1) a prototype for testing automatic flight control systems with participation of pilots; 2) a nose symmetrical relative to the fuselage rocket type cylinder axis; 3) a supposedly optimal variant based on the results of previous calculations. The aerodynamic characteristics of 3D fuselage models for positive integer Reynolds numbers (full-scale model) were calculated using the ANSYS software package. Three computational grids were built for these models in ANSYS ICEM CFD. The given version of the fuselage nose section intended for testing automatic flight control systems with participation of pilots initially has the greatest resistance among the considered variants. That is, first variant of the fuselage nose gives substantial braking zone as well as significant flow acceleration zone exists in place where fuselage is transformed into cylindrical part. The variant with the nose section symmetrical relative to the rocket type cylinder axis has smaller braking zone and less dispersed flow in place where fuselage is transformed into cylindrical part and, therefore, it has lower resistance in comparison with the first version. The fuselage execution developed on the basis of the results of previous calculations, despite the extensive acceleration zone at the junction of the nose to the cylindrical part, has shown the least resistance, respectively, and is the best of the considered variants. This is also confirmed by a comparison of streamlines over the nose surface. The streamlines are given for calculations at angle of attack of 8°; at this angle of attack, the difference in the coefficient Cx is clearly visible.

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

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.

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