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Morphing wings made a significant advancement in aircraft engineering by improving aerodynamic performance for better fuel efficiency and are still under research. This paper reviewed and investigated some morphing wing types including the variable sweep, trailing edge, leading edge, variable span, variable chord, or scale, and airfoil morphing among others. Based on the review, two types of morphing wings were chosen for detailed investigation, and they were variable span and variable scale. Each morphing concept from the selected morphing wing types was implemented in airfoil wing configuration for aerodynamic performance analysis. Computational Fluid Dynamics (CFD) simulation is used to design and analyse morphing wing configurations of the chosen morphing concepts. In this research, two CFD analyses were investigated based on wing configuration; each consists of chosen morphing concept. Before the main CFD simulation of morphing wing analysis, CFD analysis of reference data of a typical NACA 2415 airfoil was verified. The lift coefficient of the morphing wing obtained from CFD analysis was compared with the unmorphed NACA airfoil wing to evaluate the morphing wing’s aerodynamic performance. It is concluded that there is an improvement in lift coefficients using the morphing concept cases, showing improved aerodynamic performance.

Purpose The purpose of this paper is to discuss a numerical study of the flow over a wing representative of a large civil aircraft at cruise condition. For each Mach number considered, the numerical simulations indicate that critical angle of attack exists where the separated region increases in size and begins to oscillate. This phenomenon, known as transonic shock buffet, is reproduced by the unsteady simulation and much information can be extracted analysing location, amplitude and frequency content of the unsteadiness. Design/methodology/approach Reynolds-averaged Navier-Stokes simulations are conducted on a half wing-body configuration, at different Mach numbers and angles of attack. Different turbulence models are considered, and both steady-state results and time-accurate simulations are discussed. Findings The high number of cases presented in this study allows the creation of a database which, to the authors’ knowledge, has not been documented in literature before. The results indicate that, while high-fidelity approaches can improve the quality of the results, the URANS approach is capable of describing the main features of the buffet phenomenon. Research limitations/implications The presence of a turbulence model, despite allowing the description of the main unsteady phenomenon, might be insufficient to fully characterise the unsteadiness present in a transonic flow over a half wing-body configuration. Therefore, researchers are encouraged to verify by means of experimental investigation or high-fidelity approach the results issued from a Reynolds-averaged Navier-Stokes equations. Practical implications The results presented clearly indicate that, despite what proposed in recent research papers, transonic buffet can be described by means of time-accurate Reynolds-averaged Navier-Stokes equations. Such an approach is popular in the aeronautical industry because of its reduced costs, and could be used for wing design. Originality/value In this paper, the authors used a classical approach to tackle the known problem of transonic buffet in three-dimensional configurations. The large number of results presented can be used as a database for future numerical simulations and experiments, and allow to describe the flow-physics of the buffet unsteadiness on a half wing-body configuration.

This paper proposes a hybrid rigid–flexible wing design that enables large-area folding and reconfiguration. Based on elasticity theory and fabric constitutive equations, a surface-outward mechanical model incorporating mesoscale weave structures was developed for plain-woven wing membranes. To address the degradation of the model under low-prestress conditions, a more accurate second-order nonlinear model for the out-of-plane mechanics of wing membranes was further developed. This paper developed a dual-axis tensile fixture and, through conducting load-bearing performance experiments on wing membrane elements, verified that the improved theoretical model possesses a certain degree of predictive accuracy. A dual-axis tensile fixture was designed, and load-bearing tests on membrane elements were conducted to verify that the improved theoretical model provides reasonable predictive accuracy. To investigate how pre-tensioning regulates membrane stiffness, the variation in out-of-plane stiffness under symmetric and asymmetric prestress conditions was analysed. A prestressing strategy prioritising the principal-modulus direction is proposed, providing theoretical guidance for prestress application in wing membranes. Based on these findings, a prototype rigid–flexible composite wing with a “membrane-scaffold” structure was fabricated and tested.

With the rapid development of the computer capability and the continuous improvement of CFD (Computational Fluid Dynamics) technology, optimization design has gradually become a powerful and reliable means to solve the aerodynamic design problems. Among all kinds of optimization methods, gradient-based optimization algorithm can find the local optimal solution quickly, which is widely used in engineering problems. However, the computation of gradient is very expensive when an engineering problem involves large number of design variables. In this paper, an optimization method based on approximate gradient analysis is introduced, where the one-dimensional linear searches during the optimization process are evaluated with high-fidelity flow field analyses, while the gradients are evaluated with low-fidelity flow field analyses, leading to a significant saving in the computational cost of high-fidelity analysis. This method is demonstrated using a numerical example and RAE2822 airfoil optimization, and it is finally applied to the aerodynamic optimization of a wing-body configuration, which obtains good optimization results.

This study focuses on a high‐altitude long‐endurance (HALE) joined‐wing configuration UAV and completes a preliminary structural design based on aircraft design indices and the fundamental principles of aircraft structure design. Based on the preliminary structural design scheme and aerodynamic shape, a structural finite element model and a vortex lattice aerodynamic analysis model of the UAV are established, and the aerodynamic loads in typical states are obtained. The aerodynamic loads of the UAV are applied to a finite element model using the multipoint row method, and the structural static characteristics are obtained. The study further explores typical structural dynamic characteristics, including natural mode, static aeroelastic, flutter, and gust response characteristics. A comparison with the structural characteristics of a conventional configuration UAV with the same structural weight reveals that the HALE joined‐wing configuration UAV exhibits significant advantages in structural stiffness, mode characteristics, flutter characteristics, and static aeroelastic characteristics, whereas the gust response characteristics are essentially equivalent to those of the conventional configuration. This superiority can be attributed to the reduced wingspan while providing the same lift and effective support effect of the rear wing on the front (Frt) wings, which enhances the structural stiffness of high‐aspect‐ratio HALE UAVs. This configuration is particularly suitable for deployment in high‐subsonic HALE configurations that require close coordination with conventional tactical aircraft. By comparing with the structural characteristics of the conventional configuration UAV with equal structural weight, the paper comprehensively analyzes the structural characteristics of the HALE joined‐wing configuration and obtains the advantages and disadvantages of applying the joined‐wing configuration in HALE aircraft and defines the design direction, which lays a solid foundation for the engineering application in the next stage.

  A blended wing body (BWB) configuration is an unconventional aircraft design in which the wing and fuselage are blended to form an aircraft. This design concept has inherent higher aerodynamic efficiency, environmental benefits and capacities. These advantages make the BWB configuration a feasible concept for commercial transport aircraft. In the present work, a 3-D BWB model is designed in SolidWorks and fabricated using a 3D printer. The numerical and experimental analyses are carried out with this BWB geometry. Aerodynamic characteristics and flow features obtained from the open-source CFD software OpenFOAM have been studied, analyzed, and compared with the wind tunnel results. Experimental and computational data compare well and the present BWB can operate at a high angle of attack. The coefficient of lift (CL) increases with AoA up to 45º. The CL starts decreasing beyond this AoA, and the present BWB geometry stalls at around AoA = 45º. The coefficient of drag (CD) increases with the increase in AoA due to the spreading of the separated region over the geometry. Lift/Drag (L/D) variation with AoA is also studied to find the optimum flight configuration of the present BWB geometry. Sectional pressure distribution at different spanwise locations, velocity contours, pathlines, surface limiting streamlines and tuft flow visualization are also presented to investigate the flow. The studies investigate the aerodynamics, flow field and optimal flight configuration for cruising a BWB geometry.

This study was aimed description of morphological features of fruits and seeds of eight species related to Brassicaceae family in Iraq, the study showed number of taxonomic differences as the silique was long in all studied except the species Rorippa amphibian (L.)b Besser was short, however the  fruits varied in dimensions where the species Turritis laxa L. recorded the highest average length with (160 mm) while the species  R .amphibia was record  the shortest length (5 mm), in addition the colors ranged from green to brown. This study showed that all of the species was glabrous except Arabis caucasia Willd. was lanute-woolly.  The configuration shapes were linear with except the species Nasturtium officinale W.T.Aiton. was elliptic and R.amphibia was ovoid, moreover, the characteristics of   seeds were investigated as taxonomical important traits like dimensions, colors, number of seeds in fruit, surface configuration and the presence of wing, the number of seeds per species as T. laxa have about 75 seeds  in one fruit with the highest rate recorded while lowest average number of seeds among species was 12 seeds in Arabis novaVill.

Solar-powered aircraft can perform long-term flights with clean solar energy. However, the energy derived from solar irradiation is influenced by the time of year and latitude, which limits the energy acquisition ability of solar aircraft with a straight-wing configuration. Hence, unconventional configurations based on increasing wing dihedral to track the sun are proposed to improve energy acquisition at high-latitude regions in winter, which may involve power loss caused by mismatch in the photovoltaic system. However, mismatch loss is seldom considered and may cause energy to be overestimated. In this paper, the energy acquisition characteristics of a joint-wing configuration are presented based on the simulation of an energy system to investigate the mismatch power loss. The results indicate a 4~15% deviation from the frequently used estimation method and show that the mismatch loss is influenced by the curved upper surface, the severity of shading and the circuit configuration. Then, the configuration energy acquisition factor is proposed to represent the energy acquisition ability of the joint-wing configuration. Finally, the matching between the aircraft configuration and flight trajectory is analyzed, demonstrating that the solar-powered aircraft with an unconventional wing configuration is more sensitive to the coupling between configuration and trajectory.

Present work investigates the potential of a long-range commercial blended wing body configuration powered by hydrogen combustion engines with future airframe and propulsion technologies. Future technologies include advanced materials, load alleviation techniques, boundary layer ingestion, and ultra-high bypass ratio engines. The hydrogen combustion configuration was compared to the configuration powered by kerosene with respect to geometric properties, performance characteristics, energy demand, equivalent CO2 emissions, and Direct Operating Costs. In addition, technology sensitivity studies were performed to assess the potential influence of each technology on the configuration. A multi-fidelity sizing methodology using low- and mid-fidelity methods for rapid configuration sizing was created to assess the configuration and perform robust analyses and multi-disciplinary optimizations. To assess potential uncertainties of the fidelity of aerodynamic analysis tools, high-fidelity aerodynamic analysis and optimization framework MACH-Aero was used for additional verification. Comparison of hydrogen and kerosene blended wing body aircraft showed a potential reduction of equivalent CO2 emission by 15% and 81% for blue and green hydrogen compared to the kerosene blended wing body and by 44% and 88% with respect to a conventional B777-300ER aircraft. Advancements in future technologies also significantly affect the geometric layout of aircraft. Boundary layer ingestion and ultra-high bypass ratio engines demonstrated the highest potential for fuel reduction, although both technologies conflict with each other. However, operating costs of hydrogen aircraft could establish a significant problem if pessimistic and base hydrogen price scenarios are achieved for blue and green hydrogen respectively. Finally, configurational problems featured by classical blended wing body aircraft are magnified for the hydrogen case due to the significant volume requirements to store hydrogen fuel.

Purpose Unmanned aerial vehicles (UAV) with remote and/or automated flight and mission controls have replaced airplanes with pilots in many important roles. This study aims to deal with computational fluid dynamics (CFD) analysis and development of the aerodynamic configuration of a multi-purpose UAV for low and medium altitudes. The main aerodynamic requirement was the application of the tandem wing (TW) concept, where both wings generate a positive lift and act as primary lifting devices. Design/methodology/approach Initial design analyses of the UAV’s aerodynamic configuration were performed using ANSYS Fluent. In previous work in Fluent, the authors established a calculation model that has been verified by experiments and, with minor adjustments, could be applied for subsonic, transonic and supersonic flow analyses. Findings The design evolved through eight development configurations, where the latest V8 satisfied all the posted longitudinal aerodynamic requirements. Both wings generate a substantial amount of positive lift, whereas the initial stall occurs first on the front wing, generating a natural nose-down stall recovery tendency. In the cruising flight regime, this configuration has the desired range of longitudinal static stability and its centre of pressure is in close proximity to the centre of gravity. Practical implications The intermediate development version V8 with proper longitudinal aerodynamic characteristics presents a good starting point for future development steps that will involve the optimization of lateral-directional aerodynamics. Originality/value Using contemporary CFD tools, a novel and original TW aerodynamic configuration have evolved within eight development stages, not being based on or derived from any existing designs.