Trailing-edge flap is traditionally used to improve the takeoff and landing aerodynamic performance of aircraft.In order to improve flight efficiency during takeoff,cruise and landing states,the flexible variable camb...Trailing-edge flap is traditionally used to improve the takeoff and landing aerodynamic performance of aircraft.In order to improve flight efficiency during takeoff,cruise and landing states,the flexible variable camber trailing-edge flap is introduced,capable of changing its shape smoothly from 50% flap chord to the rear of the flap.Using a numerical simulation method for the case of the GA（W）-2 airfoil,the multi-objective optimization of the overlap,gap,deflection angle,and bending angle of the flap under takeoff and landing configurations is studied.The optimization results show that under takeoff configuration,the variable camber trailing-edge flap can increase lift coefficient by about 8% and lift-to-drag ratio by about 7% compared with the traditional flap at a takeoff angle of 8°.Under landing configuration,the flap can improve the lift coefficient at a stall angle of attack about 1.3%.Under cruise state,the flap helps to improve the lift-todrag ratio over a wide range of lift coefficients,and the maximum increment is about 30%.Finally,a corrugated structure–eccentric beam combination bending mechanism is introduced in this paper to bend the flap by rotating the eccentric beam.展开更多
It is important to understand the impact of wing-morphing on aerodynamic performance in the study of flapping-wing flight of birds and insects. We use a flapping plate hinged with a trailing-edge flap as a simplified ...It is important to understand the impact of wing-morphing on aerodynamic performance in the study of flapping-wing flight of birds and insects. We use a flapping plate hinged with a trailing-edge flap as a simplified model for flexible/morphing wings in hovering. The trailing-edge flapping motion is opti- mized by an adjoint-based approach. The optimized configuration suggests that the trailing-edge flap can substantially enhance the overall lift. Further analysis indicates that the lift enhancement by the trailing- edge flapping is from the change of circulation in two ways： the local circulation change by the rotational motion of the flap, and the modification of vortex shedding process by the relative location between the trailing-edge flao and leading-edge main plate.展开更多
Owls exhibit remarkably silent flight,largely attributed to trailing-edge(TE)serrations on their wings.Inspired by this biological adaptation,TE serrations have become promising passive-noise-control strategies for ae...Owls exhibit remarkably silent flight,largely attributed to trailing-edge(TE)serrations on their wings.Inspired by this biological adaptation,TE serrations have become promising passive-noise-control strategies for aerodynamic devices,including drones and wind turbines.However,conventional designs typically feature single-scale geometries—Such as sawtooth or sinusoidal serrations—that fail to replicate the owl’s inherently dual-scale morphology:Macro-scale waviness formed by feather tips combined with micro-scale morphology.Here,we introduce and evaluate a hybrid TE serration design that incorporates both macro-scale wave patterns and micro-scale fringe-like elements to closely emulate the owl wing structure.Using large-eddy simulations coupled with the Ffowcs Williams-Hawkings acoustic analogy,we assess three configurations:A smooth baseline,a conventional wavy serration,and the proposed hybrid serration.Our results indicate that the hybrid configuration achieves an overall noise reduction of about 12 dB relative to the smooth baseline,surpassing the conventional wavy configuration by approximately 2.5 dB,while preserving aerodynamic performance as measured by lift-to-drag ratio.Flow-field analyses further reveal that dual-scale serrations effectively suppress TE pressure fluctuations,highlighting a key aeroacoustic advantage of the owl-inspired hybrid approach.These insights advance our understanding of bioinspired noisecontrol mechanisms and provide practical guidelines for designing quieter aerodynamic systems.展开更多
To effectively reduce the loss of strong shock wave at the trailing edge of the supersonic cascade under high backpressure,a shock wave control method based on self-sustaining synthetic jet was proposed.The self-susta...To effectively reduce the loss of strong shock wave at the trailing edge of the supersonic cascade under high backpressure,a shock wave control method based on self-sustaining synthetic jet was proposed.The self-sustaining synthetic jet was applied on the pressure side of the blade with the blow slot and the bleed slot arranged upstream and downstream of the trailing-edge shock,respectively.The flow control mechanism and effects of parameters were investigated by numerical simulation.The results show that the self-sustaining synthetic jet forms an oblique shock wave in the cascade passage which slows down and pressurizes the airflow,and the expansion wave downstream of the blow slot weakens the shock strength which can effectively change the Mach reflection to regular reflection and thus weaken the shock loss.And the suction effect can reduce loss near blade surface.Compared with the baseline cascade,the self-sustaining jet actuator can reduce flow losses by 6.73%with proper location design and vibration of diaphragm.展开更多
Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft.Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft...Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft.Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft,but insufficiently effective for the entire flight envelope.Recent research on morphing wing still faces the challenge that the skin material for morphing should be both deformable and stiff.In this study,a continuous morphing trailing-edge wing with a new multi-stable nano skin material fabricated using surface mechanical attrition treatment technology was proposed and designed.Computational fluid dynamics simulation was used to study the aerodynamic performance of the continuous morphing trailing-edge wing.Results show that the lift coefficient increases with the increase of deflection angle and so does the lift-drag ratio at a small angle of attack.More importantly,compared with the wing using flaps,the continuous morphing trailing-edge wing can reduce drag during the morphing process and its overall aerodynamic performance is improved at a large angle of attack range.Flow field analysis reveals that the continuous morphing method can delay flow separation in some situations.展开更多
A variable camber wing driven by pneumatic artificial muscles is developed in this paper. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed and the relations...A variable camber wing driven by pneumatic artificial muscles is developed in this paper. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed and the relationship between the static output force and the air pressure is investigated. Experimental results show that the static output force of pneumatic artificial muscle decreases nonlinearly with the increase of contraction ratio. Secondly, the model of variable camber wing driven by pneumatic artificial muscles is manufactured to validate the variable camber concept. Finally, wind tunnel tests are conducted in the low speed wind tunnel. It is found that the wing camber increases with the increase of air pressure. When the air pressure of PAMs is 0.4 MPa and 0.5 MPa, the tip displacement of the trailing-edge is 3 mm and 5 mm, respectively. The lift of aerofoil with flexible trailing-edge increases by 87% at AOA of 5°.展开更多
Owls are widely known for their silent flight,which is attributed to their unique wing morphologies comprising leading-edge(LE)serrations,trailing-edge(TE)fringes,and a velvety surface.The aeroacoustic characteristics...Owls are widely known for their silent flight,which is attributed to their unique wing morphologies comprising leading-edge(LE)serrations,trailing-edge(TE)fringes,and a velvety surface.The aeroacoustic characteristics of owl-inspired TE fringes have been widely investigated through two-dimensional(2D)modeling,but remain yet poorly studied in association with their three-dimensional(3D)effects.Here,we present a numerical study of the 3D aeroacoustic characteristics of owl-inspired TE fringes in which we combined large-eddy simulations(LES)with the Ffowcs Williams‒Hawkings analogy.We constructed a clean wing model and three wing models with TE fringes that were distributed differently spanwise.The aerodynamic forces and 3D acoustic characteristics reveal that,like the 2D results of our previous studies,the 3D TE fringes enable remarkable sound reduction spatially while having aerodynamic performance comparable to the clean model.Visualizations of the near-field 3D flow structures,vortex dynamics,and flow fluctuations show that TE fringes can robustly alter the 3D flow by breaking 3D TE vortices into small eddies and mitigating 3D flow fluctuations.Particularly,it is verified that TE fringes alter spanwise flows,thus dominating the 3D aeroacoustic characteristics in terms of passive flow control and flow stabilizations,whereas the fringes are inefficient in suppressing the acoustic sources induced by wingtip vortices.Moreover,the TE fringes distributed at midspan have better acoustic performance than those in the vicinity of the wingtip,indicating the importance of a spanwise distribution in enhancing aeroacoustic performance.展开更多
Cicatricial ectropion of the eyelid is an eversion of its edge, which has moved away from the globe. It is frequently the result of cicatricial retraction after trauma. The main risk is the occurrence of a corneal ulc...Cicatricial ectropion of the eyelid is an eversion of its edge, which has moved away from the globe. It is frequently the result of cicatricial retraction after trauma. The main risk is the occurrence of a corneal ulcer or chronic conjunctivitis. Their treatment is often difficult, especially when the ectropion is old and significant. There are several classic techniques for correcting cicatricial ectropions, but the technique of the myocutaneous flap combined with external tarsorrhaphy without damage to the canthal ligament is minimally invasive, not very widespread, yet responds very well to the rules of plastic surgery. We report two cases of post-traumatic cicatricial ectropions of the left lower eyelid, respectively in a 33-year-old and an 87-year-old, treated using this technique. The surgical procedure was performed in two stages, after evaluation of the skin of the flap to be harvested: harvesting of the flap and closure plasty including external tarsorrhaphy. Patient follow-up did not note any complications. This combined technique offers a minimally invasive alternative for the often-delicate treatment of ectropions.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
Current breast reconstruction evaluations mostly focus on static cosmetic analysis as a measure of the clinical outcomes.Moreover,it is essential to consider the dynamic changes in the reconstructed breast alongside a...Current breast reconstruction evaluations mostly focus on static cosmetic analysis as a measure of the clinical outcomes.Moreover,it is essential to consider the dynamic changes in the reconstructed breast alongside assessments of aesthetic symmetry,functional restoration,complication rates,and long-term stability of the reconstruction.This study aimed to assess the mobility of the reconstructed breast following various breast reconstruction techniques,specifically by comparing deep inferior epigastric perforator(DIEP) flaps and pedicled transverse rectus abdominis musculocutaneous(TRAM) flaps.We conducted a longitudinal case study to investigate the changes in breast movement resulting from different surgical interventions.The comparison showed that DIEP flap reconstruction was more likely to achieve superior breast mobility outcomes than TRAM flap reconstruction.For a better breast aesthetic outcome,it is fundamental to improve the awareness of the dynamic evaluation of the reconstructed breast at the surgical strategy level.展开更多
Background: The lumbar artery perforator(LAP) flap is an important autologous option in breast reconstruction.As the lumbar perforator flap is relatively new in this field,several questions remain regarding preoperati...Background: The lumbar artery perforator(LAP) flap is an important autologous option in breast reconstruction.As the lumbar perforator flap is relatively new in this field,several questions remain regarding preoperative preparation,especially concerning computed tomography(CT) and magnetic resonance imaging of the donor site.The objective of this study was to aid the surgical approach to the LAP flap in female patients by precisely determining the characteristics of the lumbar perforators.Methods: We retrospectively reviewed the computed tomographic angiography images of 20 patients who underwent evaluation of the perforator positions from the four lumbar arteries.Four characteristics were studied:length,diameter,path of the lumbar pedicle,and thickness of the tissues available for transfer.Results: We analyzed 20 CT images,identifying 149 perforating vessels of the lumbar artery.The most suitable perforator for flap harvesting was the L4 perforator,which exhibited a larger diameter,a greater number of perforasomes,and a higher percentage of the cutaneous-septal tract.Conclusion: The LAP flap is a viable option for breast reconstruction and as a free flap in women.The L4 perforator artery is the most suitable for harvesting,owing to its superior perfusion capacity,diameter,and course;however,an interposition graft may be required to lengthen the vascular pedicle.展开更多
Objectives:To assess outcomes of rectourethral fistula repair utilizing a gracilis flap in a largely radiated cohort.Patients and Methods:We performed a retrospective review of all gracilis interposition flap reconstr...Objectives:To assess outcomes of rectourethral fistula repair utilizing a gracilis flap in a largely radiated cohort.Patients and Methods:We performed a retrospective review of all gracilis interposition flap reconstruction surgeries performed for RUF at a university hospital in South Carolina between January 2010 and June 2023.All repairs utilized a multidisciplinary approach with urology,colorectal,and plastic surgery teams.Postoperatively,patients were maximally drained with foley catheter and suprapubic tube(SPT).Initial voiding cystourethrogram(VCUG)was performed at 4 weeks post-repair.If there was a persistent leak,catheter drainage was maintained for 4 additional weeks and VCUG was repeated.Success was defined as absence of leak on VCUG within 3 months after surgery.Results:22 patients met inclusion criteria.68%of patients had history of external beam radiation therapy(EBRT),13.6%had brachytherapy,and 40.9%had cryotherapy.Initial post-operative VCUG was negative in 10 patients(45.5%).Of the 12 patients with a persistent fistula,5(42%)had no evidence of fistula on subsequent VCUG after 4 weeks.Overall,68%of patients were successfully treated with gracilis interposition flap.There was a significant difference of repair success based on EBRT status(p<0.05).Conclusions:We report a success rate of 68%for gracilis flap repair of RUF.Our cohort had a higher rate of prior radiation therapy compared to other studies.A clinically significant portion of patients with an initial positive VCUG will seal their fistula with prolonged catheter drainage.Gracilis interposition flap is a reasonable surgical treatment for RUF.展开更多
A robust Reynolds-Averaged Navier-Stokes(RANS)based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC)rotor.The complex motion with multiple degrees of fr...A robust Reynolds-Averaged Navier-Stokes(RANS)based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC)rotor.The complex motion with multiple degrees of freedom of the Trailing Edge Flap(TEF)is analyzed by employing an inverse nested overset grid method.Simulation of non-rotational and rotational modes of blade motion are carried out to investigate the formation and development of TEF shedding vortex with high-frequency deflection of TEF.Moreover,the mechanism of TEF deflection interference with blade tip vortex and overall rotor aerodynamics is also explored.In nonrotational mode,two bundles of vortices form at the gap ends of TEF and the main blade and merge into a single TEF vortex.Dynamic deflection of the TEF significantly interferes with the blade tip vortex.The position of the blade tip vortex consistently changes,and its frequency is directly related to the frequency of TEF deflection.In rotational mode,the tip vortex forms a helical structure.The end vortices at the gap sides co-swirl and subsequently merge into the concentrated beam of tip vortices,causing fluctuations in the vorticity and axial position of the tip vortex under the rotor.This research concludes with the investigation on suppression of Blade Vortex Interaction(BVI),showing an increase in miss distance and reduction in the vorticity of tip vortex through TEF phase control at a particular control frequency.Through this mechanism,a designed TEF deflection law increases the miss distance by 34.7%and reduces vorticity by 11.9%at the target position,demonstrating the effectiveness of AFC in mitigating BVI.展开更多
The flow control at low Reynolds numbers is one of the most promising technologies in the field of aerodynamics,and it is also an important source of the innovation for novel aircraft.In this study,a new way of nonlin...The flow control at low Reynolds numbers is one of the most promising technologies in the field of aerodynamics,and it is also an important source of the innovation for novel aircraft.In this study,a new way of nonlinear flow control by interaction between two flexible flaps is proposed,and their flow control mechanism is studied employing the self-constructed immersed boundary-lattice Boltzmann-finite element method(IB-LB-FEM).The effects of the difference in material properties and flap length between the two flexible flaps on the nonlinear flow control of the airfoil are discussed.It is suggested that the relationship between the deformation of the two flexible flaps and the evolution of the vortex under the fluid-structure interaction(FSI).It is shown that the upstream flexible flap plays a key role in the flow control of the two flexible flaps.The FSI effect of the upstream flexible flap will change the unsteady flow behind it and affect the deformation of the downstream flexible flap.Two flexible flaps with different material properties and different lengths will change their own FSI characteristics by the induced vortex,effectively suppressing the flow separation on the airfoil’s upper surface.The interaction of two flexible flaps plays an extremely important role in improving the autonomy and adjustability of flow control.The numerical results will provide a theoretical basis and technical guidance for the development and application of a new flap passive control technology.展开更多
Osteoradionecrosis of the temporal bone(ORN-TB)is usually controlled with conservative measures.However,a temporal bone resection may be required in unresponsive cases.The reconstruction of the resulting defects may b...Osteoradionecrosis of the temporal bone(ORN-TB)is usually controlled with conservative measures.However,a temporal bone resection may be required in unresponsive cases.The reconstruction of the resulting defects may be challenging because of the radiation damage to regional tissues.As a result,distant free flaps may be an optimal choice.For instance,the gracilis muscular free flap(GMFF)has consistent vascular anatomy and can be used to reconstruct small defects.We report three cases of uncontrolled ORN-TB requiring an extensive temporal bone resection followed by vascularized obliteration with a GMFF.The patients reported complete control of the main otologic symptoms(otorrhea,otalgia,and aural fullness)and optimal functional and aesthetic outcomes.Finally,the patients reported significant improvement in quality of life despite early postoperative complications.To our knowledge,the GMFF had not been used to obliterate temporal bone defects in patients with ORN-TB.展开更多
AIM:To evaluate the outcome and the degree of patient satisfaction with the reconstruction of full-thickness medial and central lower lid defects using a pendular flap of the remaining lateral part of the lower lid.ME...AIM:To evaluate the outcome and the degree of patient satisfaction with the reconstruction of full-thickness medial and central lower lid defects using a pendular flap of the remaining lateral part of the lower lid.METHODS:Totally 20 patients with full thickness medial or central lower lid defects that could not be repaired by direct closure with or without cantholysis.A sliding full-thickness composite flap was created from the lateral part of the remaining lid to cover the defect.The posterior lamella of the induced lateral defect was repaired by either a periosteal flap alone or in combination with a free tarsal graft.Postoperative cosmetic and functional outcomes were evaluated.RESULTS:The mean age of the patients was 46.3±18.1y(20-70y).The defects ranged from 30%-80%of the lid width and resulted from the excision of lid tumors in 11 patients(55%)and from trauma in 9(45%)patients.Postoperative complications included one case of lateral graft ectropion,2 cases of lid retraction and 3 cases of marginal graft necrosis.Most of the patients had an acceptable final cosmetic outcome.CONCLUSION:Reconstruction of moderate-sized defects in the medial/central lower lid via a sliding flap yielded acceptable cosmetic and functional outcomes with high patient satisfaction.Large defects≥50%of the horizontal length are at greater risk of complications.Reconstruction of medial defects by this technique was associated with a greater incidence of complications.展开更多
Soft tissue reconstruction of the radial thumb tip remains surgically challenging,particularly when standard options such as kite or Brünelli flaps are less suitable due to anatomical constraints.This technical n...Soft tissue reconstruction of the radial thumb tip remains surgically challenging,particularly when standard options such as kite or Brünelli flaps are less suitable due to anatomical constraints.This technical note presents the case of a 37-year-old male with a radial-sided distal thumb defect reconstructed using a reverse homodigital dorsoradial flap.Two key refinements were applied:preservation of approximately 5 mm of subcutaneous tissue to support venous outflow and a 3-5 mm proximal safety margin at the pivot point based on Doppler assessment to reduce pedicle tension during 180◦rotation.The flap was inset without tunneling and healed without complications.Functional recovery was confirmed by progressive improvements in the disabilities of the arm,shoulder and hand score(from 25 at 1 month to 4.2 at 1 year),normal range of motion,and two-point discrimination(from 5 mm to 4 mm).This case highlights the practical advantages of flap design refinement for radial thumb reconstruction and supports its reproducibility in similar clinical scenarios.However,as this is a single case report,further validation with studies involving multiple cases is necessary to confirm the reliability and broad applicability of these refinements.展开更多
The online version of the original article can be found at:https://www.sciopen.com/article/10.26599/JOTO.2025.9540018 Erratum to Journal of Otology,2025,20(2):123-126.https://doi.org/10.26599/JOTO.2025.9540018 The sur...The online version of the original article can be found at:https://www.sciopen.com/article/10.26599/JOTO.2025.9540018 Erratum to Journal of Otology,2025,20(2):123-126.https://doi.org/10.26599/JOTO.2025.9540018 The surnames and given names of these authors are reversed:Saro-Buendía Miguel,Andresen-Lorca Belén,Pérez-García Alberto,Llópez Carratala Nacho,Carreres Polo Joan,Armengot Carceller Miguel,Perolada Valmaña Jose María.It should be Miguel Saro-Buendía,Belén Andresen-Lorca,Alberto Pérez-García,Nacho Llópez Carratala,Joan Carreres Polo,Miguel Armengot Carceller,Jose María Perolada Valmaña.展开更多
To propel the application of a bottom-hinged flap breakwater in real sea conditions,a two-dimensional computational fluid dynamics numerical model was conducted to investigate the pitching motion response and wave att...To propel the application of a bottom-hinged flap breakwater in real sea conditions,a two-dimensional computational fluid dynamics numerical model was conducted to investigate the pitching motion response and wave attenuation in random waves.First,the flow velocity distribution characteristic of the pitching flap at typical times was summarized.Then,the effects of random wave and flap parameters on the flap’s significant pitching angle amplitude θ_(s) and hydrodynamic coefficients were investigated.The results reveal that θ_(s) and wave reflection coefficient K_(r) values increase with increasing significant wave height Hs,random wave steepnessλs,and flap relative height.As Hs andλs increase,the wave transmission coefficient K_(t) increases while the wave dissipation coefficient K_(d) decreases.Additionally,K_(t) decreases with increasing flap relative height.With increasing equivalent damping coefficient ratio,θ_(s) and K_(t) decrease,while K_(r) and K_(d) increase.The relationships betweenλs and flap relative height on the one hand andθ_(s),K_(r),K_(t),and K_(d) in random waves on the other hand are compared to those in regular waves.Based on the equal incident wave energy and the equal incident wave energy flux,the pitching flap performs better in the wave attenuation capability under random waves than in regular waves.Finally,the dimensionless parameters with respect to random wave and flap were used to derive the K_(r) and K_(t) for-mulae,which were validated with the related data.展开更多
Background:Free flap transplantation has emerged as a prevalent technique in reconstructive surgery for patients with oral cancer.Postoperative monitoring of flap perfusion is critical for flap survival,necessitating ...Background:Free flap transplantation has emerged as a prevalent technique in reconstructive surgery for patients with oral cancer.Postoperative monitoring of flap perfusion is critical for flap survival,necessitating early detection and timely intervention.Developing a monitoring approach that is highly sensitive,specific,noninvasive,continuous,and cost-effective is crucial for accurately assessing flap perfusion and informing clinical decisions.Methods:From April 2024 to December 2024,20 patients with oral tumors requiring flap transplantation were enrolled at the Ninth People’s Hospital affiliated to Shanghai Jiao Tong University School of Medicine.Continuous monitoring of various free flaps was performed utilizing a transcutaneous blood gas analyzer,both before and after surgery.This approach allowed for real-time measurement of transcutaneous partial pressure of oxygen(TcPO_(2))and transcutaneous partial pressure of carbon dioxide(TcPCO_(2)),facilitating the evaluation of perfusion dynamics across various free flap types.Results:After free flap transplantation,a reduction in blood supply resulted in a rapid decline in TcPO_(2)(to below 10 mmHg),accompanied by a gradual increase in TcPCO_(2),peaking at 135 mmHg.Following vascular anastomosis and blood flow restoration,TcPO_(2)and TcPCO_(2)exhibited opposite trends.Statistical analysis revealed no significant differences in TcPO_(2)and TcPCO_(2)measurements among the various flap types(P<0.05),indicating a consistent pattern of change across all flaps.Conclusion:The transcutaneous blood gas analyzer proves to be a reliable method for monitoring free flap perfusion.Dynamic changes in TcPO_(2)and TcPCO_(2)effectively reflect blood supply status,enabling early detection of vascular compromise and potentially enhancing flap preservation outcomes.展开更多
文摘Trailing-edge flap is traditionally used to improve the takeoff and landing aerodynamic performance of aircraft.In order to improve flight efficiency during takeoff,cruise and landing states,the flexible variable camber trailing-edge flap is introduced,capable of changing its shape smoothly from 50% flap chord to the rear of the flap.Using a numerical simulation method for the case of the GA（W）-2 airfoil,the multi-objective optimization of the overlap,gap,deflection angle,and bending angle of the flap under takeoff and landing configurations is studied.The optimization results show that under takeoff configuration,the variable camber trailing-edge flap can increase lift coefficient by about 8% and lift-to-drag ratio by about 7% compared with the traditional flap at a takeoff angle of 8°.Under landing configuration,the flap can improve the lift coefficient at a stall angle of attack about 1.3%.Under cruise state,the flap helps to improve the lift-todrag ratio over a wide range of lift coefficients,and the maximum increment is about 30%.Finally,a corrugated structure–eccentric beam combination bending mechanism is introduced in this paper to bend the flap by rotating the eccentric beam.
文摘It is important to understand the impact of wing-morphing on aerodynamic performance in the study of flapping-wing flight of birds and insects. We use a flapping plate hinged with a trailing-edge flap as a simplified model for flexible/morphing wings in hovering. The trailing-edge flapping motion is opti- mized by an adjoint-based approach. The optimized configuration suggests that the trailing-edge flap can substantially enhance the overall lift. Further analysis indicates that the lift enhancement by the trailing- edge flapping is from the change of circulation in two ways： the local circulation change by the rotational motion of the flap, and the modification of vortex shedding process by the relative location between the trailing-edge flao and leading-edge main plate.
基金supported by a Grant-in-Aid for Scientific Research of KAKENHI,Japan Society for the Promotion of Science(Grant Nos.23H01373 and 23K26068)support from the Japanese Government MEXT scholarship and the Excellent International Student Scholarship provided by Chiba University。
文摘Owls exhibit remarkably silent flight,largely attributed to trailing-edge(TE)serrations on their wings.Inspired by this biological adaptation,TE serrations have become promising passive-noise-control strategies for aerodynamic devices,including drones and wind turbines.However,conventional designs typically feature single-scale geometries—Such as sawtooth or sinusoidal serrations—that fail to replicate the owl’s inherently dual-scale morphology:Macro-scale waviness formed by feather tips combined with micro-scale morphology.Here,we introduce and evaluate a hybrid TE serration design that incorporates both macro-scale wave patterns and micro-scale fringe-like elements to closely emulate the owl wing structure.Using large-eddy simulations coupled with the Ffowcs Williams-Hawkings acoustic analogy,we assess three configurations:A smooth baseline,a conventional wavy serration,and the proposed hybrid serration.Our results indicate that the hybrid configuration achieves an overall noise reduction of about 12 dB relative to the smooth baseline,surpassing the conventional wavy configuration by approximately 2.5 dB,while preserving aerodynamic performance as measured by lift-to-drag ratio.Flow-field analyses further reveal that dual-scale serrations effectively suppress TE pressure fluctuations,highlighting a key aeroacoustic advantage of the owl-inspired hybrid approach.These insights advance our understanding of bioinspired noisecontrol mechanisms and provide practical guidelines for designing quieter aerodynamic systems.
基金co-supported by the National Natural Science Foundation of China(No.52075538)the National Science and Technology Major Project,China(No.J2019-II-0016-0037)+1 种基金the Natural Science Foundation of Hunan Province,China(No.2020 JJ2030)the Foundation of National University of Defense Technology,China(No.ZK-22-30)。
文摘To effectively reduce the loss of strong shock wave at the trailing edge of the supersonic cascade under high backpressure,a shock wave control method based on self-sustaining synthetic jet was proposed.The self-sustaining synthetic jet was applied on the pressure side of the blade with the blow slot and the bleed slot arranged upstream and downstream of the trailing-edge shock,respectively.The flow control mechanism and effects of parameters were investigated by numerical simulation.The results show that the self-sustaining synthetic jet forms an oblique shock wave in the cascade passage which slows down and pressurizes the airflow,and the expansion wave downstream of the blow slot weakens the shock strength which can effectively change the Mach reflection to regular reflection and thus weaken the shock loss.And the suction effect can reduce loss near blade surface.Compared with the baseline cascade,the self-sustaining jet actuator can reduce flow losses by 6.73%with proper location design and vibration of diaphragm.
基金This work is supported by the Major Program of National Natural Science Foundation of China(No.:NSFC51590892)the Shenzhen Municipal Science and Technology Innovation Commission of China(No.:JCYJ20160229165310679).
文摘Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft.Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft,but insufficiently effective for the entire flight envelope.Recent research on morphing wing still faces the challenge that the skin material for morphing should be both deformable and stiff.In this study,a continuous morphing trailing-edge wing with a new multi-stable nano skin material fabricated using surface mechanical attrition treatment technology was proposed and designed.Computational fluid dynamics simulation was used to study the aerodynamic performance of the continuous morphing trailing-edge wing.Results show that the lift coefficient increases with the increase of deflection angle and so does the lift-drag ratio at a small angle of attack.More importantly,compared with the wing using flaps,the continuous morphing trailing-edge wing can reduce drag during the morphing process and its overall aerodynamic performance is improved at a large angle of attack range.Flow field analysis reveals that the continuous morphing method can delay flow separation in some situations.
基金Sponsored by the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20102302120032)the Open Foundation of Key Laboratory of Advanced Composites in Special Environmentsthe Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(Grant No.HIT.NSRIF.2012028)
文摘A variable camber wing driven by pneumatic artificial muscles is developed in this paper. Firstly, the experimental setup to measure the static output force of pneumatic artificial muscle is designed and the relationship between the static output force and the air pressure is investigated. Experimental results show that the static output force of pneumatic artificial muscle decreases nonlinearly with the increase of contraction ratio. Secondly, the model of variable camber wing driven by pneumatic artificial muscles is manufactured to validate the variable camber concept. Finally, wind tunnel tests are conducted in the low speed wind tunnel. It is found that the wing camber increases with the increase of air pressure. When the air pressure of PAMs is 0.4 MPa and 0.5 MPa, the tip displacement of the trailing-edge is 3 mm and 5 mm, respectively. The lift of aerofoil with flexible trailing-edge increases by 87% at AOA of 5°.
基金supported by a Grant-in-Aid for Scientific Research of KAKENHI,Japan Society for the Promotion of Science(Grant No.19H00750)J.R.acknowledges financial support from the Japanese Government through a MEXT scholarship.
文摘Owls are widely known for their silent flight,which is attributed to their unique wing morphologies comprising leading-edge(LE)serrations,trailing-edge(TE)fringes,and a velvety surface.The aeroacoustic characteristics of owl-inspired TE fringes have been widely investigated through two-dimensional(2D)modeling,but remain yet poorly studied in association with their three-dimensional(3D)effects.Here,we present a numerical study of the 3D aeroacoustic characteristics of owl-inspired TE fringes in which we combined large-eddy simulations(LES)with the Ffowcs Williams‒Hawkings analogy.We constructed a clean wing model and three wing models with TE fringes that were distributed differently spanwise.The aerodynamic forces and 3D acoustic characteristics reveal that,like the 2D results of our previous studies,the 3D TE fringes enable remarkable sound reduction spatially while having aerodynamic performance comparable to the clean model.Visualizations of the near-field 3D flow structures,vortex dynamics,and flow fluctuations show that TE fringes can robustly alter the 3D flow by breaking 3D TE vortices into small eddies and mitigating 3D flow fluctuations.Particularly,it is verified that TE fringes alter spanwise flows,thus dominating the 3D aeroacoustic characteristics in terms of passive flow control and flow stabilizations,whereas the fringes are inefficient in suppressing the acoustic sources induced by wingtip vortices.Moreover,the TE fringes distributed at midspan have better acoustic performance than those in the vicinity of the wingtip,indicating the importance of a spanwise distribution in enhancing aeroacoustic performance.
文摘Cicatricial ectropion of the eyelid is an eversion of its edge, which has moved away from the globe. It is frequently the result of cicatricial retraction after trauma. The main risk is the occurrence of a corneal ulcer or chronic conjunctivitis. Their treatment is often difficult, especially when the ectropion is old and significant. There are several classic techniques for correcting cicatricial ectropions, but the technique of the myocutaneous flap combined with external tarsorrhaphy without damage to the canthal ligament is minimally invasive, not very widespread, yet responds very well to the rules of plastic surgery. We report two cases of post-traumatic cicatricial ectropions of the left lower eyelid, respectively in a 33-year-old and an 87-year-old, treated using this technique. The surgical procedure was performed in two stages, after evaluation of the skin of the flap to be harvested: harvesting of the flap and closure plasty including external tarsorrhaphy. Patient follow-up did not note any complications. This combined technique offers a minimally invasive alternative for the often-delicate treatment of ectropions.
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.
文摘Current breast reconstruction evaluations mostly focus on static cosmetic analysis as a measure of the clinical outcomes.Moreover,it is essential to consider the dynamic changes in the reconstructed breast alongside assessments of aesthetic symmetry,functional restoration,complication rates,and long-term stability of the reconstruction.This study aimed to assess the mobility of the reconstructed breast following various breast reconstruction techniques,specifically by comparing deep inferior epigastric perforator(DIEP) flaps and pedicled transverse rectus abdominis musculocutaneous(TRAM) flaps.We conducted a longitudinal case study to investigate the changes in breast movement resulting from different surgical interventions.The comparison showed that DIEP flap reconstruction was more likely to achieve superior breast mobility outcomes than TRAM flap reconstruction.For a better breast aesthetic outcome,it is fundamental to improve the awareness of the dynamic evaluation of the reconstructed breast at the surgical strategy level.
文摘Background: The lumbar artery perforator(LAP) flap is an important autologous option in breast reconstruction.As the lumbar perforator flap is relatively new in this field,several questions remain regarding preoperative preparation,especially concerning computed tomography(CT) and magnetic resonance imaging of the donor site.The objective of this study was to aid the surgical approach to the LAP flap in female patients by precisely determining the characteristics of the lumbar perforators.Methods: We retrospectively reviewed the computed tomographic angiography images of 20 patients who underwent evaluation of the perforator positions from the four lumbar arteries.Four characteristics were studied:length,diameter,path of the lumbar pedicle,and thickness of the tissues available for transfer.Results: We analyzed 20 CT images,identifying 149 perforating vessels of the lumbar artery.The most suitable perforator for flap harvesting was the L4 perforator,which exhibited a larger diameter,a greater number of perforasomes,and a higher percentage of the cutaneous-septal tract.Conclusion: The LAP flap is a viable option for breast reconstruction and as a free flap in women.The L4 perforator artery is the most suitable for harvesting,owing to its superior perfusion capacity,diameter,and course;however,an interposition graft may be required to lengthen the vascular pedicle.
文摘Objectives:To assess outcomes of rectourethral fistula repair utilizing a gracilis flap in a largely radiated cohort.Patients and Methods:We performed a retrospective review of all gracilis interposition flap reconstruction surgeries performed for RUF at a university hospital in South Carolina between January 2010 and June 2023.All repairs utilized a multidisciplinary approach with urology,colorectal,and plastic surgery teams.Postoperatively,patients were maximally drained with foley catheter and suprapubic tube(SPT).Initial voiding cystourethrogram(VCUG)was performed at 4 weeks post-repair.If there was a persistent leak,catheter drainage was maintained for 4 additional weeks and VCUG was repeated.Success was defined as absence of leak on VCUG within 3 months after surgery.Results:22 patients met inclusion criteria.68%of patients had history of external beam radiation therapy(EBRT),13.6%had brachytherapy,and 40.9%had cryotherapy.Initial post-operative VCUG was negative in 10 patients(45.5%).Of the 12 patients with a persistent fistula,5(42%)had no evidence of fistula on subsequent VCUG after 4 weeks.Overall,68%of patients were successfully treated with gracilis interposition flap.There was a significant difference of repair success based on EBRT status(p<0.05).Conclusions:We report a success rate of 68%for gracilis flap repair of RUF.Our cohort had a higher rate of prior radiation therapy compared to other studies.A clinically significant portion of patients with an initial positive VCUG will seal their fistula with prolonged catheter drainage.Gracilis interposition flap is a reasonable surgical treatment for RUF.
基金supported by the National Natural Science Foundation of China(No.11972190)。
文摘A robust Reynolds-Averaged Navier-Stokes(RANS)based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC)rotor.The complex motion with multiple degrees of freedom of the Trailing Edge Flap(TEF)is analyzed by employing an inverse nested overset grid method.Simulation of non-rotational and rotational modes of blade motion are carried out to investigate the formation and development of TEF shedding vortex with high-frequency deflection of TEF.Moreover,the mechanism of TEF deflection interference with blade tip vortex and overall rotor aerodynamics is also explored.In nonrotational mode,two bundles of vortices form at the gap ends of TEF and the main blade and merge into a single TEF vortex.Dynamic deflection of the TEF significantly interferes with the blade tip vortex.The position of the blade tip vortex consistently changes,and its frequency is directly related to the frequency of TEF deflection.In rotational mode,the tip vortex forms a helical structure.The end vortices at the gap sides co-swirl and subsequently merge into the concentrated beam of tip vortices,causing fluctuations in the vorticity and axial position of the tip vortex under the rotor.This research concludes with the investigation on suppression of Blade Vortex Interaction(BVI),showing an increase in miss distance and reduction in the vorticity of tip vortex through TEF phase control at a particular control frequency.Through this mechanism,a designed TEF deflection law increases the miss distance by 34.7%and reduces vorticity by 11.9%at the target position,demonstrating the effectiveness of AFC in mitigating BVI.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.92371201,52192633,11872293,and 92152301)the Natural Science Basic Research Program of Shaanxi(Grant Nos.2024JC-YBQN-0008,and 2022JC-03)+1 种基金Shaanxi Key Research and Development Program(Grant No.2022ZDLGY02-07)the Joint Natural Science Foundation of China with Guangdong Province for TianHe-II Supercomputer Resources,and the Research Start-up Foundation of Xi’an University of Science and Technology for the High-Level Talent.
文摘The flow control at low Reynolds numbers is one of the most promising technologies in the field of aerodynamics,and it is also an important source of the innovation for novel aircraft.In this study,a new way of nonlinear flow control by interaction between two flexible flaps is proposed,and their flow control mechanism is studied employing the self-constructed immersed boundary-lattice Boltzmann-finite element method(IB-LB-FEM).The effects of the difference in material properties and flap length between the two flexible flaps on the nonlinear flow control of the airfoil are discussed.It is suggested that the relationship between the deformation of the two flexible flaps and the evolution of the vortex under the fluid-structure interaction(FSI).It is shown that the upstream flexible flap plays a key role in the flow control of the two flexible flaps.The FSI effect of the upstream flexible flap will change the unsteady flow behind it and affect the deformation of the downstream flexible flap.Two flexible flaps with different material properties and different lengths will change their own FSI characteristics by the induced vortex,effectively suppressing the flow separation on the airfoil’s upper surface.The interaction of two flexible flaps plays an extremely important role in improving the autonomy and adjustability of flow control.The numerical results will provide a theoretical basis and technical guidance for the development and application of a new flap passive control technology.
文摘Osteoradionecrosis of the temporal bone(ORN-TB)is usually controlled with conservative measures.However,a temporal bone resection may be required in unresponsive cases.The reconstruction of the resulting defects may be challenging because of the radiation damage to regional tissues.As a result,distant free flaps may be an optimal choice.For instance,the gracilis muscular free flap(GMFF)has consistent vascular anatomy and can be used to reconstruct small defects.We report three cases of uncontrolled ORN-TB requiring an extensive temporal bone resection followed by vascularized obliteration with a GMFF.The patients reported complete control of the main otologic symptoms(otorrhea,otalgia,and aural fullness)and optimal functional and aesthetic outcomes.Finally,the patients reported significant improvement in quality of life despite early postoperative complications.To our knowledge,the GMFF had not been used to obliterate temporal bone defects in patients with ORN-TB.
文摘AIM:To evaluate the outcome and the degree of patient satisfaction with the reconstruction of full-thickness medial and central lower lid defects using a pendular flap of the remaining lateral part of the lower lid.METHODS:Totally 20 patients with full thickness medial or central lower lid defects that could not be repaired by direct closure with or without cantholysis.A sliding full-thickness composite flap was created from the lateral part of the remaining lid to cover the defect.The posterior lamella of the induced lateral defect was repaired by either a periosteal flap alone or in combination with a free tarsal graft.Postoperative cosmetic and functional outcomes were evaluated.RESULTS:The mean age of the patients was 46.3±18.1y(20-70y).The defects ranged from 30%-80%of the lid width and resulted from the excision of lid tumors in 11 patients(55%)and from trauma in 9(45%)patients.Postoperative complications included one case of lateral graft ectropion,2 cases of lid retraction and 3 cases of marginal graft necrosis.Most of the patients had an acceptable final cosmetic outcome.CONCLUSION:Reconstruction of moderate-sized defects in the medial/central lower lid via a sliding flap yielded acceptable cosmetic and functional outcomes with high patient satisfaction.Large defects≥50%of the horizontal length are at greater risk of complications.Reconstruction of medial defects by this technique was associated with a greater incidence of complications.
文摘Soft tissue reconstruction of the radial thumb tip remains surgically challenging,particularly when standard options such as kite or Brünelli flaps are less suitable due to anatomical constraints.This technical note presents the case of a 37-year-old male with a radial-sided distal thumb defect reconstructed using a reverse homodigital dorsoradial flap.Two key refinements were applied:preservation of approximately 5 mm of subcutaneous tissue to support venous outflow and a 3-5 mm proximal safety margin at the pivot point based on Doppler assessment to reduce pedicle tension during 180◦rotation.The flap was inset without tunneling and healed without complications.Functional recovery was confirmed by progressive improvements in the disabilities of the arm,shoulder and hand score(from 25 at 1 month to 4.2 at 1 year),normal range of motion,and two-point discrimination(from 5 mm to 4 mm).This case highlights the practical advantages of flap design refinement for radial thumb reconstruction and supports its reproducibility in similar clinical scenarios.However,as this is a single case report,further validation with studies involving multiple cases is necessary to confirm the reliability and broad applicability of these refinements.
文摘The online version of the original article can be found at:https://www.sciopen.com/article/10.26599/JOTO.2025.9540018 Erratum to Journal of Otology,2025,20(2):123-126.https://doi.org/10.26599/JOTO.2025.9540018 The surnames and given names of these authors are reversed:Saro-Buendía Miguel,Andresen-Lorca Belén,Pérez-García Alberto,Llópez Carratala Nacho,Carreres Polo Joan,Armengot Carceller Miguel,Perolada Valmaña Jose María.It should be Miguel Saro-Buendía,Belén Andresen-Lorca,Alberto Pérez-García,Nacho Llópez Carratala,Joan Carreres Polo,Miguel Armengot Carceller,Jose María Perolada Valmaña.
基金supported by the National Natural Science Foundation of China(Nos.52271295,52088102).
文摘To propel the application of a bottom-hinged flap breakwater in real sea conditions,a two-dimensional computational fluid dynamics numerical model was conducted to investigate the pitching motion response and wave attenuation in random waves.First,the flow velocity distribution characteristic of the pitching flap at typical times was summarized.Then,the effects of random wave and flap parameters on the flap’s significant pitching angle amplitude θ_(s) and hydrodynamic coefficients were investigated.The results reveal that θ_(s) and wave reflection coefficient K_(r) values increase with increasing significant wave height Hs,random wave steepnessλs,and flap relative height.As Hs andλs increase,the wave transmission coefficient K_(t) increases while the wave dissipation coefficient K_(d) decreases.Additionally,K_(t) decreases with increasing flap relative height.With increasing equivalent damping coefficient ratio,θ_(s) and K_(t) decrease,while K_(r) and K_(d) increase.The relationships betweenλs and flap relative height on the one hand andθ_(s),K_(r),K_(t),and K_(d) in random waves on the other hand are compared to those in regular waves.Based on the equal incident wave energy and the equal incident wave energy flux,the pitching flap performs better in the wave attenuation capability under random waves than in regular waves.Finally,the dimensionless parameters with respect to random wave and flap were used to derive the K_(r) and K_(t) for-mulae,which were validated with the related data.
基金supported by the Fundamental Research Program(grant no.:JYZZ228)the Clinical Research Booster Program(grant no.JYLJ202311)of the Shanghai Ninth Peoples’Hospital of Shanghai Jiao Tong University School of Medicine.
文摘Background:Free flap transplantation has emerged as a prevalent technique in reconstructive surgery for patients with oral cancer.Postoperative monitoring of flap perfusion is critical for flap survival,necessitating early detection and timely intervention.Developing a monitoring approach that is highly sensitive,specific,noninvasive,continuous,and cost-effective is crucial for accurately assessing flap perfusion and informing clinical decisions.Methods:From April 2024 to December 2024,20 patients with oral tumors requiring flap transplantation were enrolled at the Ninth People’s Hospital affiliated to Shanghai Jiao Tong University School of Medicine.Continuous monitoring of various free flaps was performed utilizing a transcutaneous blood gas analyzer,both before and after surgery.This approach allowed for real-time measurement of transcutaneous partial pressure of oxygen(TcPO_(2))and transcutaneous partial pressure of carbon dioxide(TcPCO_(2)),facilitating the evaluation of perfusion dynamics across various free flap types.Results:After free flap transplantation,a reduction in blood supply resulted in a rapid decline in TcPO_(2)(to below 10 mmHg),accompanied by a gradual increase in TcPCO_(2),peaking at 135 mmHg.Following vascular anastomosis and blood flow restoration,TcPO_(2)and TcPCO_(2)exhibited opposite trends.Statistical analysis revealed no significant differences in TcPO_(2)and TcPCO_(2)measurements among the various flap types(P<0.05),indicating a consistent pattern of change across all flaps.Conclusion:The transcutaneous blood gas analyzer proves to be a reliable method for monitoring free flap perfusion.Dynamic changes in TcPO_(2)and TcPCO_(2)effectively reflect blood supply status,enabling early detection of vascular compromise and potentially enhancing flap preservation outcomes.
