The ability of queens and males of most ant species to disperse by flight has fundamentally contributed to the group’s evolutionary and ecological success and is a determining factor to take into account for biogeogr...The ability of queens and males of most ant species to disperse by flight has fundamentally contributed to the group’s evolutionary and ecological success and is a determining factor to take into account for biogeographic studies(Wagner and Liebherr 1992;Peeters and Ito 2001;Helms 2018).展开更多
Avian wings are central to their remarkable flight ability and diverse life history strategies,including behaviors such as fighting and mating.These multifaceted functions are intricately tied to wing shape,which vari...Avian wings are central to their remarkable flight ability and diverse life history strategies,including behaviors such as fighting and mating.These multifaceted functions are intricately tied to wing shape,which varies significantly across species because of the complex interplay of evolutionary and ecological pressures.Many indices have been developed to quantify wing characteristics to facilitate the study and comparison of avian wing morphology across species.This study provides a comprehensive overview of existing quantitative methods for analyzing avian wing shapes.We then constructed a new quantification framework through the beta distribution,which can generate indices reflecting the shape of avian wings(center,dispersion,skewness,and kurtosis).Next,we used the flight feathers of 613 bird species to perform different quantitative analyses and explore the relationships between various wing shape quantification methods and life history traits,which serve as proxies for the selective forces shaping wing morphology.We find that the wing shape indices are more strongly associated with ecological variables than with morphological variables,especially for migration,habitat and territoriality.This research guides the selection of appropriate methods for wing shape analysis,contributing to a deeper understanding of avian morphology and its evolutionary drivers.展开更多
Aeroelastic control is a critical technique for high-aspect-ratio flexible wings.A novel aeroelastic control method is introduced,utilizing the internal Moving Mass Control(MMC)technique,which demonstrates the potenti...Aeroelastic control is a critical technique for high-aspect-ratio flexible wings.A novel aeroelastic control method is introduced,utilizing the internal Moving Mass Control(MMC)technique,which demonstrates the potential to fulfill hybrid control demands without incurring a drag penalty.Dynamic equations for a flexible wing equipped with a spanwise moving mass under unsteady aerodynamic loading are derived using mass position as the input variable.Controloriented analyses indicate that intrinsic structural frequencies,flutter characteristics,and gust response can be actively modified by varying the spanwise and chordwise positions of the mass element.Among these,the chordwise position exerts a more significant impact on the structural modes and flutter speed of the wing.A hybrid aeroelastic control system,incorporating motion planning and control law,is proposed to evaluate real-time performance in Active Flutter Suppression(AFS)and Gust Load Alleviation(GLA).Control outcomes suggest that,with a mass ratio of 1/16 and a half-chord installation area for the guide rail,flutter speed increases by about 10%.Additionally,excitation amplitudes across different gust frequencies are substantially mitigated,achieving a maximum reduction of vibration amplitude by about 73%.These findings offer a comprehensive understanding of the MMC technique and its application to flexible aircraft.展开更多
This paper introduces an innovative approach to the deployment of folding wings on cruise missiles,aiming to overcome the issues associated with explosive devices.The proposed solution involves employing NiTi shape me...This paper introduces an innovative approach to the deployment of folding wings on cruise missiles,aiming to overcome the issues associated with explosive devices.The proposed solution involves employing NiTi shape memory wires for a nonexplosive self-deploying wing mechanism.The fundamental concept of the design revolves around the utilization of NiTi wires,which contract upon electric heating.This contraction action severs the shear pin,consequently releasing the folded wings.The operational performance of the NiTi wire is thoroughly examined through a series of electro-thermo-mechanical tests,offering valuable insights for selecting the appropriate wire material.Moreover,the mechanical dynamics involved in the self-deploying process are elucidated through finite element simulations.The simulations highlight that the thermally-induced phase transformation within the NiTi wires generates substantial actuation forces,exceeding 700 N,and strokes of over 6 mm.These forces are deemed sufficient for breaking the aluminum shear pin and effecting wing deployment.The proposed mechanism’s practical viability is substantiated through prototype tests,which conclusively establish the superiority of the nonexplosive self-deploying wing mechanism when compared to conventional methods.The experimental outcomes underscore the mechanism’s capability to markedly reduce overload stress while remaining compliant with the designated requirements and constraints.展开更多
This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-dis...This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-distributed trailing-edge camber morphing is established based on Chebyshev polynomials,and the deformed wing surface is modeled by a spline surface according to the rib's morphing in the chordwise direction.The Computational Fluid Dynamics(CFD)method is adopted to obtain flow-field results and aerodynamic forces.The SST-γmodel is introduced and the overset mesh technique is adopted.The numerical results show that the spanwisedistributed trailing-edge morphing obviously changes the aerodynamic and energy transfer characteristics of the dynamic stall.Especially when the phase difference between the trailing-edge motion and the wing pitch is-π/2,the interaction between the three-dimensional(3-D)Leading-Edge Vortex(LEV)and Trailing-Edge Vortex(TEV)is strengthened,and the work done by the aerodynamic force turns negative.This indicates that the trailing-edge deformation has the potential to suppress the oscillation amplitude of stall flutter.We also found that as the trailing-edge camber morphing varies more complexly along the spanwise direction,the suppression effect decreases accordingly.展开更多
Superhydrophobic/superhydrophilic antifouling materials are widely used to solve the severe water pollution and bio-adhesion of marine equipment.However,conventional antifouling materials rely on the static superwetta...Superhydrophobic/superhydrophilic antifouling materials are widely used to solve the severe water pollution and bio-adhesion of marine equipment.However,conventional antifouling materials rely on the static superwettability of surfaces,which suffer from poorly sustained antifouling effects.Inspired by the unique dynamic antifouling strategies of Calliphora Vicina wing surface based on the hydrophobic micro-cilia arrays,a Biomimetic Magnetic-Responsive Antifouling Surface(BMRAS)is designed and fabricated using a method combining UV lithography and an inverse molding.The BMRAS is coated by high-aspect-ratio micro-cilia,which are filled with synthesized magnetic Fe3O4 nanoparticles.The bioinspired hydrophobic micro-cilia arrays endow the BMRAS with excellent intrinsic superhydrophobicity,benefiting from the high-aspect-ratio feature and roughness effect.Remarkably,the static contact angle is more than 156.9±1.6°and the rolling angle is less than 2.3±0.3°.The synthesized magnetic nanomaterials play a key role in implementing dynamic antifouling strategies.On the one hand,the surface tension can be adjusted as required under magnetically controlled oscillations.On the other hand,the doping of magnetic nanomaterials can enhance mechanical properties and reduce capillary force-induced aggregation of high-aspect-ratio micro-cilia.The antifouling tests demonstrate that the chemically modified micro-cilia can effectively expel gravels under the stimulation of an external magnetic field and enable the BMRAS to achieve dynamic self-cleaning.Specifically,0.17 g gravel distributed on BMRAS can be completely cleaned up within 0.296 s,which improved by 14.2%compared with the flat materials.This work provides a brief and effective strategy for designing dynamic antifouling surfaces with excellent physicochemical durability and great potential value in the applications of marine fouling.展开更多
The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise int...The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise intensity than the wingless load.Due to the severe aerodynamic instability prior to separation,the head-up or head-down phenomena are more evident and the test accuracy significantly decreases.The high-precision computer fluid dynamics and aeroacoustic analysis are employed to explore the multifield coupling mechanism of a rocket sled with the winged payload in the wide speed range(Ma=0.5–2).The results show that as the incoming velocity increases,the cone angle of the shock wave of the rocket sled decreases,the shock pressure increases quickly,and the vortex between the slippers splits and gradually shrinks in size.The velocity of the rocket sled exerts little influence on the modal resonance frequency.The wing has a significant impact on aerodynamic noise,and as the sound pressure level rises,the propagation direction gradually shifts towards the rear and upper regions of the wing.展开更多
The flying-wing aircraft has excellent aerodynamic efficiency and stealth performance.However,due to the lack of tails,the flying-wing aircraft has a serious attitude control problem.In this paper,the effective flow c...The flying-wing aircraft has excellent aerodynamic efficiency and stealth performance.However,due to the lack of tails,the flying-wing aircraft has a serious attitude control problem.In this paper,the effective flow control strategy of three-axis control is proposed by using continuous jets for a flapless flying-wing aircraft.The wind tunnel test of two kinds of flying-wing models,namely one flow control model and one mechanical control model,is conducted,and the control effect is analyzed and compared.By simultaneous blowing of the circulation control actuators inboard and differential blowing of the circulation control actuators outboard,the pitch and roll controls are achieved,respectively.It also has an effective control effect at very large angles of attack where the conventional control surface fails.A linear relationship is found between the increment of the controlled aerodynamic force/moment coefficient and the momentum coefficient for circulation control actuators.Moreover,to resolve the difficulty in yaw control,a novel wingtip jet is proposed based on the concept of the all-moving tip and compared with apex jet and circulation control jet.It is found that the wingtip jet is the most efficient actuator,followed by the simultaneous-blowing circulation control jet.Therefore,based on the research above,two optimized fluidic control configurations are proposed.One employs circulation control jet and wingtip jet,and the other is completely dependent on circulation control jet.Finally,the flow control mechanism of circulation control is discussed.Circulation control significantly accelerates the flow on the upper surface of the airfoil in attached flow and reduces the flow separation region in separated flow,leading to aerodynamic performance improvement.These results provide an important theoretic basis for the flapless flight control of flying-wing aircraft.展开更多
Modeling the dynamics of flapping wing aerial vehicle is challenging due to the complexity of aerodynamic effects and mechanical structures.The aim of this work is to develop an accurate dynamics model of flapping win...Modeling the dynamics of flapping wing aerial vehicle is challenging due to the complexity of aerodynamic effects and mechanical structures.The aim of this work is to develop an accurate dynamics model of flapping wing aerial vehicle based on real flight data.We propose a modeling framework that combines rigid body dynamics with a neural network to predict aerodynamic effects.By incorporating the concept of flapping phase,we significantly enhance the network’s ability to analyze transient aerodynamic behavior.We design and utilize a phase-functioned neural network structure for aerodynamic predictions and train the network using real flight data.Evaluation results show that the network can predict aerodynamic effects and demonstrate clear physical significance.We verify that the framework can be used for dynamic propagation and is expected to be utilized for building simulators for flapping wing aerial vehicles.展开更多
To delay the vortex breakdown position of the slender delta wing,this study innovativelyproposes the application of control near the Leading-Edge Vortex(LEV)core sweeping path,whichis called Coupled Core Rotation Dual...To delay the vortex breakdown position of the slender delta wing,this study innovativelyproposes the application of control near the Leading-Edge Vortex(LEV)core sweeping path,whichis called Coupled Core Rotation Dual Synthetic Jets(CCR-DSJ)control.The results show that thevortex breakdown points at each angle of attack are moved backward after control,and the max-imum delayed displacement is 32.4%of the root chord at 30°.Besides,there is a linear relationshipbetween the breakdown position and the angle of attack after control,indicating that CCR-DSJcontrol has a significant effect on the pressure gradient of the vortex axis.Furthermore,the lift coef-ficient C_(L)is enhanced after control,with a maximum CLincrement of 0.078 at 27°,and an effectiveincrement interval of[25°,32°].This interval is different from most previous studies,which isdirectly related to the position of the actuators.According to the lift change mechanism,the anglesof attack are divided into three stages:Stage 1(a=15°–25°),Stage 2(a=25°–32°),and Stage 3(a=32°–40°).In conclusion,CCR-DSJ control can significantly change the pressure distribution,thereby offering promising prospects for the flight stage of the slender delta wing.展开更多
The optimization of wings typically relies on computationally intensive high-fidelity simulations,which restrict the quick exploration of design spaces.To address this problem,this paper introduces a methodology dedic...The optimization of wings typically relies on computationally intensive high-fidelity simulations,which restrict the quick exploration of design spaces.To address this problem,this paper introduces a methodology dedicated to optimizing box wing configurations using low-fidelity data driven machine learning approach.This technique showcases its practicality through the utilization of a tailored low-fidelity machine learning technique,specifically designed for early-stage wing configuration.By employing surrogate model trained on small dataset derived from low-fidelity simulations,our method aims to predict outputs within an acceptable range.This strategy significantly mitigates computational costs and expedites the design exploration process.The methodology's validation relies on its successful application in optimizing the box wing of PARSIFAL,serving as a benchmark,while the primary focus remains on optimizing the newly designed box wing by Bionica.Applying this method to the Bionica configuration led to a notable 14%improvement in overall aerodynamic effciency.Furthermore,all the optimized results obtained from machine learning model undergo rigorous assessments through the high-fidelity RANS analysis for confirmation.This methodology introduces innovative approach that aims to streamline computational processes,potentially reducing the time and resources required compared to traditional optimization methods.展开更多
This paper aims to design a morphing wing with both Flexible Leading Edge(FLE)and Flexible Trailing Edge(FTE)by using cellular structures,which can help the wing boost the deformation to a greater extent on the premis...This paper aims to design a morphing wing with both Flexible Leading Edge(FLE)and Flexible Trailing Edge(FTE)by using cellular structures,which can help the wing boost the deformation to a greater extent on the premise that the weight is not changed,so as to play a greater role in aerodynamic control such as gust interference.First,as for structural design,based on NACA0012,a morphing wing model constructed by 3 forms of cell structures is proposed.Then,the aerodynamic characteristics under the interference of FLE and FTE are calculated by the Computational Fluid Dynamic(CFD)method.After the surrogate model is established to predict the lift coefficient of the wing effectively,the sensitivity analysis reveals that the main sensitivity index of FTE deflection angle β is 0.565,which has the greatest influence on the lift coefficient.And the total sensitivity index of FLE deflection angle γ is increased by 78.9%,which reveals a strong coupling relationship between FLE and FTE.Finally,using Finite Element Analysis(FEA)method and experiment,the deformation capability of the model under certain static loads are obtained.The results reveal that the maximum deflection angle of the morphing wing model can be±22°at FLE and±64°at FTE,indicating strong structural stiffness and resistance to bending breakage of the model.The presented results can be useful in the design of the cellular morphing wing with multiple flexible systems.展开更多
The ecdysone-induced transcription factor E93 in model insects plays multiple roles in the insect metamorphosis processes,such as remodeling larval tissues and determining adult tissue formation.The knockdown of E93in...The ecdysone-induced transcription factor E93 in model insects plays multiple roles in the insect metamorphosis processes,such as remodeling larval tissues and determining adult tissue formation.The knockdown of E93in insects leads to incomplete metamorphosis,suggesting that E93 is a potential target for pest control.In this study,the HaE93 gene in the cotton bollworm Helicoverpa armigera,a polyphagous pest of various commercial crops worldwide,was identified and found to have high expression in the egg,prepupal,and pupal stages.The injection of ds HaE93 induced about 60%mortality in H.armigera at the larval-pupal stage.About 30%survived but showed delayed pupation and abnormal wings,and the females developed reduced ovaries.Therefore,about 90%of the HaE93 knockdown individuals failed to reproduce before they died.The results of qRT-PCR showed that the expression levels of ecdysone primary-response genes,chitin synthesis-related genes,and wing and ovary development-related genes were reduced in HaE93 knockdown H.armigera.These results indicated that HaE93plays a critical role in larva-pupa-adult metamorphosis and the development of the cuticle,wing,and ovary in female H.armigera by regulating the expression of the associated genes.Bioassays of ds HaE93 administered by either oral delivery or injection showed similar knockdown results,which suggested that HaE93 can be used as a target gene for the RNAi control of the pest H.armigera.展开更多
To obtain the certificate of airworthiness,it is essential to conduct a full-scale aircraft static test.During such test,accurate and comprehensive wing deformation measurement is crucial for assessing its strength,st...To obtain the certificate of airworthiness,it is essential to conduct a full-scale aircraft static test.During such test,accurate and comprehensive wing deformation measurement is crucial for assessing its strength,stiffness,and bearing capability.This paper proposes a novel and cost-effective videogrammetric method using multi-camera system to achieve the non-contact,highprecision,and 3D measurement of overall static deformation for the large-scale wing structure.To overcome the difficulties of making,carrying,and employing the large 2D or 3D target for calibrating the cameras with large field of view,a flexible stereo cameras calibration method combining 1D target and epipolar geometry is proposed.The global calibration method,aided by a total station,is employed to unify the 3D data obtained from various binocular subsystems.A series of static load tests using a 10-meter-long large-scale wing have been conducted to validate the proposed system and methods.Furthermore,the proposed method was applied to the practical wing deformation measurement of both wings with a wingspan of 33.6 m in the full-size civil aircraft static test.The overall 3D profile and displacement data of the tested wing under various loads can be accurately obtained.The maximum error of distance and displacement measurement is less than 4.5 mm within the measurement range of 35 m in all load cases.These results demonstrate that the proposed method achieves effective,high-accuracy,on-site,and visualized wing deformation measurement,making it a promising approach for full-scale aircraft wing static test.展开更多
The Distributed Propulsion Wing(DPW)presents prominent advantages in terms of energy conservation during flight,but the intense integration of propulsive internal flow with aerodynamic external flow brings significant...The Distributed Propulsion Wing(DPW)presents prominent advantages in terms of energy conservation during flight,but the intense integration of propulsive internal flow with aerodynamic external flow brings significant design challenges.To tackle this issue,this paper undertakes a comprehensive investigation of the aero-propulsive coupling performance of the DPW under both hovering and cruising conditions,and subsequently proposes a multi-level collaboration optimization design method based on the decomposition principle.Specifically,the complex 3D surfaces of DPW are systematically dissociated into simple 2D curves with inherent relationships for design.The decomposition is achieved based on the analysis results of the aero-propulsive coupling characteristics.And a DPW design case is conducted and subsequently analyzed in order to further validate the effectiveness and feasibility of the proposed design method.It is shown that a 115.75%drag reduction of DPW can be achieved at cruise under a specified thrust level.Furthermore,the DPW exhibits inherent characteristics of consistent lift-to-drag ratio with the thrust-drag balance constraint,regardless of variations in incoming flow velocity or total thrust.展开更多
Based on research into bionic butterflies for environmental detection and ecological management,a scheme was proposed to develop and manufacture a bionic aircraft with two wings inspired by specific butterfly species....Based on research into bionic butterflies for environmental detection and ecological management,a scheme was proposed to develop and manufacture a bionic aircraft with two wings inspired by specific butterfly species.A flapping-wing aircraft with a simple structure was designed,and its two-wing design was optimized.The research focused on several key areas:the design and optimization of the wings,the development of the transmission mechanism,hardware design and fabrication,and 3D printing for component manufacturing.This resulted in the bionic replication of the wing shape and structure of the Tiger Papilio butterfly.The final bionic butterfly features a wingspan of 29.5 cm and a total weight of 13.8 g.This project integrates mechatronic principles and provides a valuable reference for advancements in the field of bionic butterflies.Future research could explore the aerodynamic characteristics of wings and innovative design approaches in greater depth.展开更多
Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing tech...Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight characteristics.The investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting surface.The focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type gust.At a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction simulations.First,the numerical results are validated by experimental data from force and moment,flow field,and deformation measurements.Second,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic membrane.For all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical results.During the decay of the gust,they differ more the higher the aspect ratio of the wing.When considering the flow field,the main differences are due to the separation behavior on the upper side of the wing.The flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the former.Only at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.展开更多
Birds and bats retract and stretch their wings dynamically during each flap in level flights, implying intriguing mechanisms for the aerodynamic performance improvement of flapping wings. A numerical investigation int...Birds and bats retract and stretch their wings dynamically during each flap in level flights, implying intriguing mechanisms for the aerodynamic performance improvement of flapping wings. A numerical investigation into the aerodynamic effects of such bio-inspired concept in forward flights has been performed based on a three-dimensional wing in plunging motion and a twosection wing in flapping motion. The currently considered Reynolds number and Strouhal number are Re=1.5×10^(5) and St=0.3, respectively. During the research, the mean angle of attack is varied in relatively wide ranges to achieve lift-thrust interconversion for the wings. The conclusive results show that dynamical spanwise retraction and stretch has induced three absolutely desirable scenarios for the oscillating wings in forward flights, namely producing more lift and consuming less power for a given thrust generation, producing more thrust and consuming less power for a given lift generation, and producing more lift and more thrust while consuming less power. Furthermore,the morphing wings have alleviated periodical aerodynamic load fluctuations compared with the non-morphing baseline. The mechanism of the aerodynamic effects of the bionic morphing mode is analyzed with the aid of field visualization. The current article is the first to reveal the absolute advantages of the bionic spanwise morphing. Hopefully, it may help comprehend the behaviors of natural fliers and provide inspirations for performance enhancement of micro artificial flappingwing vehicles.展开更多
基金funded by the“Departments of Excellence”program of the Italian Ministry for University and Research(MIUR,2018-2022 and MUR,2023-2027).
文摘The ability of queens and males of most ant species to disperse by flight has fundamentally contributed to the group’s evolutionary and ecological success and is a determining factor to take into account for biogeographic studies(Wagner and Liebherr 1992;Peeters and Ito 2001;Helms 2018).
基金supported by the National Natural Science Foundation of China(No.32170491)the Scientific Research Team Project of the College of Life Sciences,Beijing Normal University in 2024。
文摘Avian wings are central to their remarkable flight ability and diverse life history strategies,including behaviors such as fighting and mating.These multifaceted functions are intricately tied to wing shape,which varies significantly across species because of the complex interplay of evolutionary and ecological pressures.Many indices have been developed to quantify wing characteristics to facilitate the study and comparison of avian wing morphology across species.This study provides a comprehensive overview of existing quantitative methods for analyzing avian wing shapes.We then constructed a new quantification framework through the beta distribution,which can generate indices reflecting the shape of avian wings(center,dispersion,skewness,and kurtosis).Next,we used the flight feathers of 613 bird species to perform different quantitative analyses and explore the relationships between various wing shape quantification methods and life history traits,which serve as proxies for the selective forces shaping wing morphology.We find that the wing shape indices are more strongly associated with ecological variables than with morphological variables,especially for migration,habitat and territoriality.This research guides the selection of appropriate methods for wing shape analysis,contributing to a deeper understanding of avian morphology and its evolutionary drivers.
基金supported by the National Natural Science Foundation of China(No.12102096)the Guangdong Basic and Applied Basic Research Foundation,China(No.2022A1515011885)the Research Fund of National Key Laboratory of Aerospace Physics in Fluids,China(No.2024-APF-KFQMJJ-08)。
文摘Aeroelastic control is a critical technique for high-aspect-ratio flexible wings.A novel aeroelastic control method is introduced,utilizing the internal Moving Mass Control(MMC)technique,which demonstrates the potential to fulfill hybrid control demands without incurring a drag penalty.Dynamic equations for a flexible wing equipped with a spanwise moving mass under unsteady aerodynamic loading are derived using mass position as the input variable.Controloriented analyses indicate that intrinsic structural frequencies,flutter characteristics,and gust response can be actively modified by varying the spanwise and chordwise positions of the mass element.Among these,the chordwise position exerts a more significant impact on the structural modes and flutter speed of the wing.A hybrid aeroelastic control system,incorporating motion planning and control law,is proposed to evaluate real-time performance in Active Flutter Suppression(AFS)and Gust Load Alleviation(GLA).Control outcomes suggest that,with a mass ratio of 1/16 and a half-chord installation area for the guide rail,flutter speed increases by about 10%.Additionally,excitation amplitudes across different gust frequencies are substantially mitigated,achieving a maximum reduction of vibration amplitude by about 73%.These findings offer a comprehensive understanding of the MMC technique and its application to flexible aircraft.
基金Supported by National Natural Science Foundation of China(Grant No.12372156).
文摘This paper introduces an innovative approach to the deployment of folding wings on cruise missiles,aiming to overcome the issues associated with explosive devices.The proposed solution involves employing NiTi shape memory wires for a nonexplosive self-deploying wing mechanism.The fundamental concept of the design revolves around the utilization of NiTi wires,which contract upon electric heating.This contraction action severs the shear pin,consequently releasing the folded wings.The operational performance of the NiTi wire is thoroughly examined through a series of electro-thermo-mechanical tests,offering valuable insights for selecting the appropriate wire material.Moreover,the mechanical dynamics involved in the self-deploying process are elucidated through finite element simulations.The simulations highlight that the thermally-induced phase transformation within the NiTi wires generates substantial actuation forces,exceeding 700 N,and strokes of over 6 mm.These forces are deemed sufficient for breaking the aluminum shear pin and effecting wing deployment.The proposed mechanism’s practical viability is substantiated through prototype tests,which conclusively establish the superiority of the nonexplosive self-deploying wing mechanism when compared to conventional methods.The experimental outcomes underscore the mechanism’s capability to markedly reduce overload stress while remaining compliant with the designated requirements and constraints.
基金co-supported by the National Natural Science Foundation of China(No.12472332)。
文摘This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-distributed trailing-edge camber morphing is established based on Chebyshev polynomials,and the deformed wing surface is modeled by a spline surface according to the rib's morphing in the chordwise direction.The Computational Fluid Dynamics(CFD)method is adopted to obtain flow-field results and aerodynamic forces.The SST-γmodel is introduced and the overset mesh technique is adopted.The numerical results show that the spanwisedistributed trailing-edge morphing obviously changes the aerodynamic and energy transfer characteristics of the dynamic stall.Especially when the phase difference between the trailing-edge motion and the wing pitch is-π/2,the interaction between the three-dimensional(3-D)Leading-Edge Vortex(LEV)and Trailing-Edge Vortex(TEV)is strengthened,and the work done by the aerodynamic force turns negative.This indicates that the trailing-edge deformation has the potential to suppress the oscillation amplitude of stall flutter.We also found that as the trailing-edge camber morphing varies more complexly along the spanwise direction,the suppression effect decreases accordingly.
基金supported by the National Key Research and Development Program of China(2023YFB4605700)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52021003)+4 种基金the National Outstanding Youth Science Fund Project of National Natural Science Foundation of China(No.52222509)the Natural Science Foundation of Jilin Province(No.20220101220JC)the Defense Industrial Technology Development Program(JCKY2023130C001)Changbai Talents Plan of Jilin Province“Fundamental Research Funds for the Central Universities”.
文摘Superhydrophobic/superhydrophilic antifouling materials are widely used to solve the severe water pollution and bio-adhesion of marine equipment.However,conventional antifouling materials rely on the static superwettability of surfaces,which suffer from poorly sustained antifouling effects.Inspired by the unique dynamic antifouling strategies of Calliphora Vicina wing surface based on the hydrophobic micro-cilia arrays,a Biomimetic Magnetic-Responsive Antifouling Surface(BMRAS)is designed and fabricated using a method combining UV lithography and an inverse molding.The BMRAS is coated by high-aspect-ratio micro-cilia,which are filled with synthesized magnetic Fe3O4 nanoparticles.The bioinspired hydrophobic micro-cilia arrays endow the BMRAS with excellent intrinsic superhydrophobicity,benefiting from the high-aspect-ratio feature and roughness effect.Remarkably,the static contact angle is more than 156.9±1.6°and the rolling angle is less than 2.3±0.3°.The synthesized magnetic nanomaterials play a key role in implementing dynamic antifouling strategies.On the one hand,the surface tension can be adjusted as required under magnetically controlled oscillations.On the other hand,the doping of magnetic nanomaterials can enhance mechanical properties and reduce capillary force-induced aggregation of high-aspect-ratio micro-cilia.The antifouling tests demonstrate that the chemically modified micro-cilia can effectively expel gravels under the stimulation of an external magnetic field and enable the BMRAS to achieve dynamic self-cleaning.Specifically,0.17 g gravel distributed on BMRAS can be completely cleaned up within 0.296 s,which improved by 14.2%compared with the flat materials.This work provides a brief and effective strategy for designing dynamic antifouling surfaces with excellent physicochemical durability and great potential value in the applications of marine fouling.
基金supported by the National Natural Science Foundation of China(No.12104047)。
文摘The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise intensity than the wingless load.Due to the severe aerodynamic instability prior to separation,the head-up or head-down phenomena are more evident and the test accuracy significantly decreases.The high-precision computer fluid dynamics and aeroacoustic analysis are employed to explore the multifield coupling mechanism of a rocket sled with the winged payload in the wide speed range(Ma=0.5–2).The results show that as the incoming velocity increases,the cone angle of the shock wave of the rocket sled decreases,the shock pressure increases quickly,and the vortex between the slippers splits and gradually shrinks in size.The velocity of the rocket sled exerts little influence on the modal resonance frequency.The wing has a significant impact on aerodynamic noise,and as the sound pressure level rises,the propagation direction gradually shifts towards the rear and upper regions of the wing.
文摘The flying-wing aircraft has excellent aerodynamic efficiency and stealth performance.However,due to the lack of tails,the flying-wing aircraft has a serious attitude control problem.In this paper,the effective flow control strategy of three-axis control is proposed by using continuous jets for a flapless flying-wing aircraft.The wind tunnel test of two kinds of flying-wing models,namely one flow control model and one mechanical control model,is conducted,and the control effect is analyzed and compared.By simultaneous blowing of the circulation control actuators inboard and differential blowing of the circulation control actuators outboard,the pitch and roll controls are achieved,respectively.It also has an effective control effect at very large angles of attack where the conventional control surface fails.A linear relationship is found between the increment of the controlled aerodynamic force/moment coefficient and the momentum coefficient for circulation control actuators.Moreover,to resolve the difficulty in yaw control,a novel wingtip jet is proposed based on the concept of the all-moving tip and compared with apex jet and circulation control jet.It is found that the wingtip jet is the most efficient actuator,followed by the simultaneous-blowing circulation control jet.Therefore,based on the research above,two optimized fluidic control configurations are proposed.One employs circulation control jet and wingtip jet,and the other is completely dependent on circulation control jet.Finally,the flow control mechanism of circulation control is discussed.Circulation control significantly accelerates the flow on the upper surface of the airfoil in attached flow and reduces the flow separation region in separated flow,leading to aerodynamic performance improvement.These results provide an important theoretic basis for the flapless flight control of flying-wing aircraft.
基金supported by National Natural Science Foundation of China under Grant No.62236007the specialized research projects of Huanjiang Laboratory.
文摘Modeling the dynamics of flapping wing aerial vehicle is challenging due to the complexity of aerodynamic effects and mechanical structures.The aim of this work is to develop an accurate dynamics model of flapping wing aerial vehicle based on real flight data.We propose a modeling framework that combines rigid body dynamics with a neural network to predict aerodynamic effects.By incorporating the concept of flapping phase,we significantly enhance the network’s ability to analyze transient aerodynamic behavior.We design and utilize a phase-functioned neural network structure for aerodynamic predictions and train the network using real flight data.Evaluation results show that the network can predict aerodynamic effects and demonstrate clear physical significance.We verify that the framework can be used for dynamic propagation and is expected to be utilized for building simulators for flapping wing aerial vehicles.
基金supported by the National Natural Science Foundation of China(Nos.92271110,12072352)the Major National Science and Technology Project,China(No.J2019-Ⅲ-0010-0054)。
文摘To delay the vortex breakdown position of the slender delta wing,this study innovativelyproposes the application of control near the Leading-Edge Vortex(LEV)core sweeping path,whichis called Coupled Core Rotation Dual Synthetic Jets(CCR-DSJ)control.The results show that thevortex breakdown points at each angle of attack are moved backward after control,and the max-imum delayed displacement is 32.4%of the root chord at 30°.Besides,there is a linear relationshipbetween the breakdown position and the angle of attack after control,indicating that CCR-DSJcontrol has a significant effect on the pressure gradient of the vortex axis.Furthermore,the lift coef-ficient C_(L)is enhanced after control,with a maximum CLincrement of 0.078 at 27°,and an effectiveincrement interval of[25°,32°].This interval is different from most previous studies,which isdirectly related to the position of the actuators.According to the lift change mechanism,the anglesof attack are divided into three stages:Stage 1(a=15°–25°),Stage 2(a=25°–32°),and Stage 3(a=32°–40°).In conclusion,CCR-DSJ control can significantly change the pressure distribution,thereby offering promising prospects for the flight stage of the slender delta wing.
基金The funding for this publication was provided by Johannes Kepler University(JKU),Linz.Special thanks to Prof.Zongmin DENG from Beihang University for his invaluable guidance,insightful feedback,and constructive criticism,which greatly enhanced the quality of this manuscript.We extend our heartfelt gratitude to the PARSIFAL team for providing the supporting materials,which inspired this study.
文摘The optimization of wings typically relies on computationally intensive high-fidelity simulations,which restrict the quick exploration of design spaces.To address this problem,this paper introduces a methodology dedicated to optimizing box wing configurations using low-fidelity data driven machine learning approach.This technique showcases its practicality through the utilization of a tailored low-fidelity machine learning technique,specifically designed for early-stage wing configuration.By employing surrogate model trained on small dataset derived from low-fidelity simulations,our method aims to predict outputs within an acceptable range.This strategy significantly mitigates computational costs and expedites the design exploration process.The methodology's validation relies on its successful application in optimizing the box wing of PARSIFAL,serving as a benchmark,while the primary focus remains on optimizing the newly designed box wing by Bionica.Applying this method to the Bionica configuration led to a notable 14%improvement in overall aerodynamic effciency.Furthermore,all the optimized results obtained from machine learning model undergo rigorous assessments through the high-fidelity RANS analysis for confirmation.This methodology introduces innovative approach that aims to streamline computational processes,potentially reducing the time and resources required compared to traditional optimization methods.
基金co-supported by the National Natural Science Foundation of China(No.52402460)project funded by the China Postdoctoral Science Foundation(No.2024T171113)supported by the Fundamental Research Funds for the Central Universities,China。
文摘This paper aims to design a morphing wing with both Flexible Leading Edge(FLE)and Flexible Trailing Edge(FTE)by using cellular structures,which can help the wing boost the deformation to a greater extent on the premise that the weight is not changed,so as to play a greater role in aerodynamic control such as gust interference.First,as for structural design,based on NACA0012,a morphing wing model constructed by 3 forms of cell structures is proposed.Then,the aerodynamic characteristics under the interference of FLE and FTE are calculated by the Computational Fluid Dynamic(CFD)method.After the surrogate model is established to predict the lift coefficient of the wing effectively,the sensitivity analysis reveals that the main sensitivity index of FTE deflection angle β is 0.565,which has the greatest influence on the lift coefficient.And the total sensitivity index of FLE deflection angle γ is increased by 78.9%,which reveals a strong coupling relationship between FLE and FTE.Finally,using Finite Element Analysis(FEA)method and experiment,the deformation capability of the model under certain static loads are obtained.The results reveal that the maximum deflection angle of the morphing wing model can be±22°at FLE and±64°at FTE,indicating strong structural stiffness and resistance to bending breakage of the model.The presented results can be useful in the design of the cellular morphing wing with multiple flexible systems.
基金supported by the National Natural Science Foundation of China(32001912 and 32370525)the Henan Provincial Natural Science Foundation,China(232300420012)。
文摘The ecdysone-induced transcription factor E93 in model insects plays multiple roles in the insect metamorphosis processes,such as remodeling larval tissues and determining adult tissue formation.The knockdown of E93in insects leads to incomplete metamorphosis,suggesting that E93 is a potential target for pest control.In this study,the HaE93 gene in the cotton bollworm Helicoverpa armigera,a polyphagous pest of various commercial crops worldwide,was identified and found to have high expression in the egg,prepupal,and pupal stages.The injection of ds HaE93 induced about 60%mortality in H.armigera at the larval-pupal stage.About 30%survived but showed delayed pupation and abnormal wings,and the females developed reduced ovaries.Therefore,about 90%of the HaE93 knockdown individuals failed to reproduce before they died.The results of qRT-PCR showed that the expression levels of ecdysone primary-response genes,chitin synthesis-related genes,and wing and ovary development-related genes were reduced in HaE93 knockdown H.armigera.These results indicated that HaE93plays a critical role in larva-pupa-adult metamorphosis and the development of the cuticle,wing,and ovary in female H.armigera by regulating the expression of the associated genes.Bioassays of ds HaE93 administered by either oral delivery or injection showed similar knockdown results,which suggested that HaE93 can be used as a target gene for the RNAi control of the pest H.armigera.
文摘To obtain the certificate of airworthiness,it is essential to conduct a full-scale aircraft static test.During such test,accurate and comprehensive wing deformation measurement is crucial for assessing its strength,stiffness,and bearing capability.This paper proposes a novel and cost-effective videogrammetric method using multi-camera system to achieve the non-contact,highprecision,and 3D measurement of overall static deformation for the large-scale wing structure.To overcome the difficulties of making,carrying,and employing the large 2D or 3D target for calibrating the cameras with large field of view,a flexible stereo cameras calibration method combining 1D target and epipolar geometry is proposed.The global calibration method,aided by a total station,is employed to unify the 3D data obtained from various binocular subsystems.A series of static load tests using a 10-meter-long large-scale wing have been conducted to validate the proposed system and methods.Furthermore,the proposed method was applied to the practical wing deformation measurement of both wings with a wingspan of 33.6 m in the full-size civil aircraft static test.The overall 3D profile and displacement data of the tested wing under various loads can be accurately obtained.The maximum error of distance and displacement measurement is less than 4.5 mm within the measurement range of 35 m in all load cases.These results demonstrate that the proposed method achieves effective,high-accuracy,on-site,and visualized wing deformation measurement,making it a promising approach for full-scale aircraft wing static test.
基金co-supported by the Equipment Advance Research Project of China(No.50911040803)the National Defense Pre-research Foundation of China(No.2021-JCJQJJ-0805)the Aeronautical Science Foundation of China(No.2024Z006053001)。
文摘The Distributed Propulsion Wing(DPW)presents prominent advantages in terms of energy conservation during flight,but the intense integration of propulsive internal flow with aerodynamic external flow brings significant design challenges.To tackle this issue,this paper undertakes a comprehensive investigation of the aero-propulsive coupling performance of the DPW under both hovering and cruising conditions,and subsequently proposes a multi-level collaboration optimization design method based on the decomposition principle.Specifically,the complex 3D surfaces of DPW are systematically dissociated into simple 2D curves with inherent relationships for design.The decomposition is achieved based on the analysis results of the aero-propulsive coupling characteristics.And a DPW design case is conducted and subsequently analyzed in order to further validate the effectiveness and feasibility of the proposed design method.It is shown that a 115.75%drag reduction of DPW can be achieved at cruise under a specified thrust level.Furthermore,the DPW exhibits inherent characteristics of consistent lift-to-drag ratio with the thrust-drag balance constraint,regardless of variations in incoming flow velocity or total thrust.
基金2023 Innovation and Entrepreneurship Training Project of Hunan College Students:Tiger Butterfly—Bionic Manufacturing and Morphology Research(Project No.S202313809022)Key Project of Education Reform of Hunan Provincial Department of Education:Research on Disciplinary Integration Education Model under Intelligence+Empowerment—A Case Study of Robotics and Logistics Management Majors(Project No.HNJG-20231561)。
文摘Based on research into bionic butterflies for environmental detection and ecological management,a scheme was proposed to develop and manufacture a bionic aircraft with two wings inspired by specific butterfly species.A flapping-wing aircraft with a simple structure was designed,and its two-wing design was optimized.The research focused on several key areas:the design and optimization of the wings,the development of the transmission mechanism,hardware design and fabrication,and 3D printing for component manufacturing.This resulted in the bionic replication of the wing shape and structure of the Tiger Papilio butterfly.The final bionic butterfly features a wingspan of 29.5 cm and a total weight of 13.8 g.This project integrates mechatronic principles and provides a valuable reference for advancements in the field of bionic butterflies.Future research could explore the aerodynamic characteristics of wings and innovative design approaches in greater depth.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)(No.BR 1511/12-1)。
文摘Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight characteristics.The investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting surface.The focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type gust.At a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction simulations.First,the numerical results are validated by experimental data from force and moment,flow field,and deformation measurements.Second,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic membrane.For all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical results.During the decay of the gust,they differ more the higher the aspect ratio of the wing.When considering the flow field,the main differences are due to the separation behavior on the upper side of the wing.The flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the former.Only at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.
基金mainly supported by the National Natural Science Foundation of China (No. 52175277, 52275293)Resources provided by the Basic Research Program of Shenzhen, China (No. JCYJ 20190806142816524)the Guangdong Basic and Applied Basic Research Foundation, China (No. 2023A1515010774)。
文摘Birds and bats retract and stretch their wings dynamically during each flap in level flights, implying intriguing mechanisms for the aerodynamic performance improvement of flapping wings. A numerical investigation into the aerodynamic effects of such bio-inspired concept in forward flights has been performed based on a three-dimensional wing in plunging motion and a twosection wing in flapping motion. The currently considered Reynolds number and Strouhal number are Re=1.5×10^(5) and St=0.3, respectively. During the research, the mean angle of attack is varied in relatively wide ranges to achieve lift-thrust interconversion for the wings. The conclusive results show that dynamical spanwise retraction and stretch has induced three absolutely desirable scenarios for the oscillating wings in forward flights, namely producing more lift and consuming less power for a given thrust generation, producing more thrust and consuming less power for a given lift generation, and producing more lift and more thrust while consuming less power. Furthermore,the morphing wings have alleviated periodical aerodynamic load fluctuations compared with the non-morphing baseline. The mechanism of the aerodynamic effects of the bionic morphing mode is analyzed with the aid of field visualization. The current article is the first to reveal the absolute advantages of the bionic spanwise morphing. Hopefully, it may help comprehend the behaviors of natural fliers and provide inspirations for performance enhancement of micro artificial flappingwing vehicles.
