scholarly journals Enhanced flight performance in non-uniformly flexible wings

2020 ◽  
Vol 17 (168) ◽  
pp. 20200352 ◽  
Author(s):  
Lionel Vincent ◽  
Min Zheng ◽  
John H. Costello ◽  
Eva Kanso
Keyword(s):  
Performance Improvement ◽  
Universal Design ◽  
Design Rule ◽  
Scaling Analysis ◽  
Flight Performance ◽  
Flexible Wings ◽  
Induced Drag ◽  
Flight Range ◽  
Potential Improvement ◽  
Convergent Design

The flexibility of biological propulsors such as wings and fins is believed to contribute to the higher performance of flying and swimming animals compared with their engineered peers. Flexibility seems to follow a universal design rule that induces bending patterns at about one-third from the distal tip of the propulsor’s span. However, the aerodynamic mechanisms that shaped this convergent design and the potential improvement in performance are not well understood. Here, we analyse the effect of heterogeneous flexibility on the flight performance (range and descent angle) of passively tumbling wings. Using experiments, numerical simulations, and scaling analysis, we demonstrate that spanwise tip flexibility that follows this empirical rule leads to improved flight performance. Improvement in flight range seems to be related to flutter-induced drag reduction. This mechanism is independent of the wing’s auto-rotation and represents a more general trait of wings with non-uniform tip flexibility.

scholarly journals Variable cant angle winglets for improvement of aircraft flight performance

Meccanica ◽  
2020 ◽  
Vol 55 (10) ◽  
pp. 1917-1947
Author(s):  
J. E. Guerrero ◽  
M. Sanguineti ◽  
K. Wittkowski
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Fuel Efficiency ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Sweep Angle ◽  
Aircraft Flight ◽  
Induced Drag ◽  
Aircraft Performance

Abstract Traditional winglets are designed as fixed devices attached at the tips of the wings. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving aircraft performance and fuel efficiency. However, because winglets are fixed surfaces, they cannot be used to control lift-induced drag reductions or to obtain the largest lift-induced drag reductions at different flight conditions (take-off, climb, cruise, loitering, descent, approach, landing, and so on). In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different flight phases. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle on the performance of a benchmark wing at Mach numbers of 0.3 and 0.8395. The results obtained demonstrate that by adjusting the cant angle, the aerodynamic performance can be improved at different flight conditions.

Optimal Scheduling of Control Surfaces Flexible Wings to Reduce Induced Drag

2006 ◽  
Vol 43 (6) ◽  
pp. 1655-1661 ◽  
Author(s):  
Raymond M. Kolonay ◽  
Franklin E. Eastep
Keyword(s):  
Optimal Scheduling ◽  
Flexible Wings ◽  
Induced Drag ◽  
Control Surfaces

scholarly journals Variable Cant Angle Winglets for Improvement of Aircraft Flight Performance

2019 ◽  
Author(s):  
Joel Guerrero ◽  
Kevin Wittkowski ◽  
Marco Sanguineti
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Fuel Efficiency ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Sweep Angle ◽  
Aircraft Flight ◽  
Induced Drag ◽  
Aircraft Performance

Traditional winglets are designed as fixed devices attached at the tips of the wings. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving aircraft performance and fuel efficiency. However, because winglets are fixed surfaces, they cannot be used to control lift-induced drag reductions or to obtain the largest lift-induced drag reductions at different flight conditions (take-off, climb, cruise, loitering, descent, approach, landing, and so on). In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different flight phases. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle on the performance of a benchmark wing at Mach numbers of 0.3 and 0.8395. The results obtained demonstrate that by adjusting the cant angle, the aerodynamic performance can be improved at different flight conditions.

Giant performance improvement of triboelectric nanogenerator systems achieved by matched inductor design

2021 ◽  
Author(s):  
Zhao Wang ◽  
Qian Tang ◽  
Chuncai Shan ◽  
Yan Du ◽  
Wencong He ◽  
...  
Keyword(s):  
Performance Improvement ◽  
Universal Design ◽  
Design Strategy ◽  
Triboelectric Nanogenerator ◽  
Theory And Experiments

We proposed a universal design strategy of a matched inductor for TENG with parameters studied from both theory and experiments systematically. The results show giant performance improvement for TENG system.

scholarly journals Design and Mechanical Analysis of Bionic Foldable Beetle Wings

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Caidong Wang ◽  
Chen Wang ◽  
Yu Ning ◽  
Lumin Chen ◽  
Xinjie Wang
Keyword(s):  
Dihedral Angle ◽  
Dynamic Models ◽  
Kinematic Model ◽  
Mechanical Analysis ◽  
Physical Parameters ◽  
Flight Performance ◽  
Motion Simulation ◽  
Flexible Wings ◽  
The Relationship ◽  
Novel Design

In order to improve the flight performance of collapsible aircrafts, a novel mechanism of bionic foldable wings of beetle is designed based on the four-plate mechanism theory. The folding and unfolding movements of the bionic foldable wings are driven by motor and torsion hinges. Based on the D-H method, a kinematic model of wings is established to analyze the dihedral angle of adjacent plates. The folding ratio of an area in different plate creasing angles has been derived and calculated. Utilizing the kinematic and static models produced, as well as considering the folding ratio and output motor torque, the optimal physical parameters of folding wings are obtained. Dynamic models of rigid and flexible wings were established using ADAMS, and a motion simulation was performed. The relationship between dihedral angle and torque during the folding process of both rigid and flexible wings was obtained. The results provide a better understanding of the folding mechanism through the formulation of rigid-flexible wing analysis, as well as demonstrating a novel design of insect-mimicking artificial wings for small aerial vehicles.

scholarly journals Comparative aerodynamic performance of flapping flight in two bat species using time-resolved wake visualization

2011 ◽  
Vol 8 (63) ◽  
pp. 1418-1428 ◽  
Author(s):  
Florian T. Muijres ◽  
L. Christoffer Johansson ◽  
York Winter ◽  
Anders Hedenström
Keyword(s):  
Movement Ecology ◽  
Ecological Factors ◽  
Reynolds Numbers ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Flexible Wings ◽  
Time Resolved ◽  
Image Velocimetry ◽  
Bat Wing ◽  
Wing Performance

Bats are unique among extant actively flying animals in having very flexible wings, controlled by multi-jointed fingers. This gives the potential for fine-tuned active control to optimize aerodynamic performance throughout the wingbeat and thus a more efficient flight. But how bat wing performance scales with size, morphology and ecology is not yet known. Here, we present time-resolved fluid wake data of two species of bats flying freely across a range of flight speeds using stereoscopic digital particle image velocimetry in a wind tunnel. From these data, we construct an average wake for each bat species and speed combination, which is used to estimate the flight forces throughout the wingbeat and resulting flight performance properties such as lift-to-drag ratio ( L/D ). The results show that the wake dynamics and flight performance of both bat species are similar, as was expected since both species operate at similar Reynolds numbers ( Re ) and Strouhal numbers ( St ). However, maximum L/D is achieved at a significant higher flight speed for the larger, highly mobile and migratory bat species than for the smaller non-migratory species. Although the flight performance of these bats may depend on a range of morphological and ecological factors, the differences in optimal flight speeds between the species could at least partly be explained by differences in their movement ecology.

The Aerodynamic Characteristics of Winglet and Effect on the Performance of the Flight

2013 ◽  
Vol 765-767 ◽  
pp. 34-37
Author(s):  
Xiu Juan Liu ◽  
Chun Guang Wang ◽  
Lei Ming ◽  
Tie Yu Hu ◽  
Jin Yu
Keyword(s):  
Aerodynamic Characteristics ◽  
Wing Surface ◽  
Tip Vortex ◽  
Advanced Technology ◽  
Practical Significance ◽  
Flight Performance ◽  
Side Force ◽  
Induced Drag ◽  
Airplane Wing ◽  
Wing Tip

Winglet is a kind of advanced technology. It is similar to the small wings of the wing surface, below approximately perpendicular to the wing surface, as long as the curvature and installation direction of winglet matched the local airflow properly, the winglet on the inward side force can inhibit the airplane wing tip vortex, reduce the induced drag. This paper introduces the cause of induced drag and the aerodynamic characteristics of the winglet,Further discusses the influence on plane flight performance, including level flight ,climbing and gliding. This knowledge will be of practical significance for guiding flight.

scholarly journals Формування областей основних параметрів модифікацій транспортного літака за умовами його базування

2021 ◽  
pp. 11-19
Author(s):  
Олександр Захарович Двейрін ◽  
Віктор Іванович Рябков ◽  
Людмила Валеріївна Капітанова ◽  
Марина Володимирівна Кириленко
Keyword(s):  
Decision Making ◽  
Performance Indicators ◽  
Early Stage ◽  
Weight Ratio ◽  
Flight Performance ◽  
Transport Aircraft ◽  
Operating Rules ◽  
Flight Range ◽  
Engine Failure ◽  
Maximum Thrust

Along with the unique flight performance indicators and economic indicators that characterize heavy transport aircraft, the priority is also to ensure the basing for their heavier modifications at the airfields declared for the base aircraft. This problem arises at the very early stage of the modification creation, when its main parameters such as the gross mass at takeoff  and thrust-to-weight ratio  are formed. This is due to the very essence of creating a modification ‑ increasing its carrying capacity (which leads to increase in the gross mass at takeoff  and flight range ) with an increased payload  by increasing the mass of fuel on board. Ensuring growth of flight  and hour , performance underlies the creation of all modifications of transport category aircraft. For heavier modifications than their base aircraft, it is further complicated by the fact that the base models are based on the runways of the second and first class airfields, which creates an insurmountable limitation on the available runway length. The second limitation is the value of the decision-making speed  during takeoff, in case of failure of the critical engine during the takeoff run, which predetermines the required length of the runway. Since the takeoff masses of aircraft modifications of this type continue to increase, the problem of their basing on the runways of existing airfields arises by forming the takeoff weight relationship  – decision-making speed in case of a critical engine failure  ‑ thrust-to-weight ratio, providing the basing of a heavier modification at the airfield declared for the base aircraft . To implement this condition, a model for determining the speed , in which a safe termination of the takeoff run is possible in the event of a critical engine failure. The resulting model allows to take into account a number of restrictions due to the properties of heavy aircraft, such as the minimum and maximum thrust of the cruise engines, which makes it possible to make reasonable recommendations in the operating rules for aircraft of this type. Taking into account the expressions obtained to determine , a model has been formed to determine and assess the required thrust-to-weight ratio of a heavier modification  by condition for modifications with a takeoff weight of more than 300 tons. It has been established that the required relative thrust-to-weight ratio should be within . Defining parameters such as ,  and  is the basis for the implementation of other modification changes in the heavy transport aircraft.

scholarly journals Computational numerical analysis of drag force on a standard AeroDesign wing in accordance with winglet application

2021 ◽  
Vol 7 (4) ◽  
Author(s):  
Hygor Vaz de Souza Barbosa ◽  
Júlio Cesar Costa Campos ◽  
Antonio Marcos de Oliveira Siqueira ◽  
Caio Vieira Hilário ◽  
Natália de Oliveira Faria ◽  
...  
Keyword(s):  
Drag Force ◽  
Lift Force ◽  
Flight Performance ◽  
Structural Components ◽  
Aerodynamic Efficiency ◽  
Drag Forces ◽  
Induced Drag ◽  
Ansys Cfx ◽  
Wing Tips ◽  
Winglet Height

This work goal is to achieve a better flight performance and to support the loading of the highest payload possible. The aerodynamics sector works to improve the aircraft aerodynamic efficiency; therefore, the aerodynamicist looks for the best solution to contribute to the aircraft efficiency by reducing drag forces. The induced drag comes from the lift force, it is related to the escape vortices which occur at the wing tips and it is the most relevant drag component. The use of structural components, as winglets, helps to reduce these vortices and the total aircraft drag. In the context of the SAE Brazil AeroDesign competition, the use of these components can support the project requirements due to the regulatory restrictions. The methodology employed was a simulation using the ANSYS CFX® software for wings modeled with different winglet configurations and the same boundary conditions to verify the best application for the studied wing. The winglet dihedral angle was set at 45°, the strings were maintained and the winglet height was used as a parameter. In the simulations, the wing attack angle was varied to obtain the variation of the drag force. With the obtained results, it was possible to verify that the wings lift forces with h=10% of the half-span winglet have lower values of drag force and present higher values of lift force, for all the analyzed angles, with a variation of up to 6 N of lift force, regarding to the wing without winglet. It is concluded the possibility to observe an improvement in the performance of the wing with the application of the winglet, in the above-mentioned context, and the compensation of a higher efficiency can help competition teams to carry more load on the aircraft due to the lift increase, and to assist the aircraft takeoff and landing handling.

scholarly journals Simulation Analysis of the Aerodynamic Performance of a Bionic Aircraft with Foldable Beetle Wings in Gliding Flight

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Caidong Wang ◽  
Yu Ning ◽  
Xinjie Wang ◽  
Junqiu Zhang ◽  
Liangwen Wang
Keyword(s):  
Simulation Analysis ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Elastic Model ◽  
Flight Performance ◽  
Flexible Wings ◽  
Gliding Flight ◽  
Drag Ratio ◽  
Gliding Movement

Beetles have excellent flight performance. Based on the four-plate mechanism theory, a novel bionic flapping aircraft with foldable beetle wings was designed. It can perform flapping, gliding, wing folding, and abduction/adduction movements with a self-locking function. In order to study the flight characteristics of beetles and improve their gliding performance, this paper used a two-way Fluid-Structure Interaction (FSI) numerical simulation method to focus on the gliding performance of the bionic flapping aircraft. The effects of elastic model, rigid and flexible wing, angle of attack, and velocity on the aerodynamic characteristics of the aircraft in gliding flight are analyzed. It was found that the elastic modulus of the flexible hinges has little effect on the aerodynamic performance of the aircraft. Both the rigid and the flexible wings have a maximum lift-to-drag ratio when the attack angle is 10°. The lift increased with the increase of the gliding speed, and it was found that the lift cannot support the gliding movement at low speeds. In order to achieve gliding, considering the weight and flight performance, the weight of the microair vehicle is controlled at about 3 g, and the gliding speed is guaranteed to be greater than 6.5 m/s. The results of this study are of great significance for the design of bionic flapping aircrafts.

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