scholarly journals Effect of Wing-Wing Interaction on the Propulsive Performance of Two Flapping Wings at Biplane Configuration

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jianyang Zhu ◽  
Bin Lei
Keyword(s):  
Numerical Analysis ◽  
Numerical Method ◽  
Phase Angle ◽  
Incompressible Flow ◽  
Underwater Vehicle ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Propulsive Performance ◽  
Wing Interaction ◽  
Systematic Synthesis

The biplane counter-flapping wing is a special type of wing flapping which is inspired from the fish and insect in nature. The propulsive performance is one of the most important considerations for this kind of flapping wing. This paper is aimed at providing a systematic synthesis on the propulsive characteristics of two flapping wings at biplane configuration based on the numerical analysis approach. Firstly, parameters of this special flapping wing are presented. Secondly, the numerical method for simultaneously solving the incompressible flow and counter-flapping motion of the wing is illustrated, and the method is then validated. Thirdly, the effects of phase angle and mean wing spacing on the propulsive characteristics of the biplane counter-flapping wing are analyzed. Finally, the quantification effects of the phase angle and mean wing spacing on the propulsive characteristics of the biplane counter-flapping wing can be obtained. The analysis results in this study will provide useful guidelines to design an effectively propulsive system applying for the flapping micro air or underwater vehicle.

scholarly journals Aerodynamic Performance of the Three-Dimensional Lumped Flexibility Bionic Hovering Wing

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Zhu Jianyang ◽  
Jiang Lin ◽  
Hou Yu
Keyword(s):  
Numerical Analysis ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Flapping Wing ◽  
Iterative Coupling ◽  
Insect Wing ◽  
Flexible Wing ◽  
At Resonance ◽  
Systematic Synthesis

Understanding the effect of flexibility on the aerodynamic characteristics of the wing is one of the most important considerations for successfully designing a flapping wing micro aero vehicle (FMAV). This paper aims at providing a systematic synthesis on the flexibility effects on the hovering performance of the bionic wing based on the numerical analysis approach. We construct a novel three-dimensional bionic wing, which has lumped flexibility at the root, and develop an iterative coupling program to simulate the interaction between the flexible wing and fluid. The effects of flexibility on the hovering performance of the three-dimensional flapping wing are investigated, and the results indicate that the best performance of the wing is achieved when the wing flaps at resonance and has the density close to the natural insect wing. The feasibility of using lumped flexibility wings driven by a simple harmonic flapping for designing efficient FMAV is also concluded in this study.

Adsorption on heterogeneous surfaces: Numerical analysis of models for the Dubinin-Radushkevich equation

1981 ◽  
Vol 46 (8) ◽  
pp. 1709-1721 ◽  
Author(s):  
Miloš Smutek ◽  
Arnošt Zukal
Keyword(s):  
Integral Equation ◽  
Numerical Analysis ◽  
Numerical Method ◽  
Adsorption Behaviour ◽  
Heterogeneous Surfaces ◽  
Strong Energy ◽  
Adsorption On Heterogeneous Surfaces ◽  
Heterogeneity Parameter ◽  
Adsorption Energies ◽  
Mobile Adsorption

A numerical method, based on the integral equation of the adsorption on energy heterogeneous surfaces, is suggested for the evaluation of overall isotherm. It is shown that for the distribution of adsorption energies given by Eq. (1.11) and different models of the adsorption behaviour, the overall isotherms obey approximately the Dubinin-Radushkevich equation. The strong energy heterogeneity smears effectively the differences between the localized and mobile adsorption and leads to the same character of the overall isotherm with only a slightly changed heterogeneity parameter.

scholarly journals Footprints of a flapping wing

2017 ◽  
Vol 818 ◽  
pp. 1-4 ◽  
Author(s):  
Jun Zhang
Keyword(s):  
Flow Pattern ◽  
External Force ◽  
Thrust Force ◽  
Flow Patterns ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Left Behind ◽  
Full Picture

Birds have to flap their wings to generate the needed thrust force, which powers them through the air. But how exactly do flapping wings create such force, and at what amplitude and frequency should they operate? These questions have been asked by many researchers. It turns out that much of the secret is hidden in the wake left behind the flapping wing. Exemplified by the study of Andersen et al. (J. Fluid Mech., vol. 812, 2017, R4), close examination of the flow pattern behind a flapping wing will inform us whether the wing is towed by an external force or able to generate a net thrust force by itself. Such studies are much like looking at the footprints of terrestrial animals as we infer their size and weight, figuring out their walking and running gaits. A map that displays the collection of flow patterns after a flapping wing, using flapping frequency and amplitude as the coordinates, offers a full picture of its flying ‘gaits’.

scholarly journals Numerical analysis of stress distribution generated in spherical polyethylene inserts by knee joint endoprotheses’ sleds

2019 ◽  
Vol 21 (2) ◽  
pp. 1-5
Author(s):  
Marcin Nabrdalik ◽  
Michał Sobociński
Keyword(s):  
Numerical Analysis ◽  
Finite Elements ◽  
Stress Distribution ◽  
Knee Joint ◽  
Titanium Alloys ◽  
Numerical Method ◽  
Ti6al4v Alloy ◽  
Finite Elements Method ◽  
Weak Points ◽  
Metal Materials

Abstract The paper presents analysis of stress distribution in the friction node of knee joint endoprosthesis where sleds are made of various titanium alloys and CoCrMo cooperate with spherical polyethylene inserts. Currently used titanium alloys consists of Nb, Ta, Zr or Mo and with lesser value of Young’s modulus than Ti6Al4V alloy, or steel CoCrMo, which significantly varies from other metal materials. The obtained results make it possible to indicate the “weak points” of the accepted solution, and thus counteract the subsequent effects resulting from premature wear of endoprosthesis elements. The analysis was conducted with numerical method of ADINA System 8.6. The Finite Elements Method allowed to compute and present stress distribution quickly in all elements of the model.

Coalescence Characteristics of Fusible Particles in Solderable Isotropic Conductive Adhesives (ICAs)

2008 ◽  
Vol 580-582 ◽  
pp. 213-216
Author(s):  
Seong Hyuk Lee ◽  
Jung Hee Lee ◽  
Jin Woon Lee ◽  
Jong Min Kim
Keyword(s):  
Numerical Analysis ◽  
Numerical Method ◽  
Volume Fraction ◽  
Conductive Adhesive ◽  
Conductive Adhesives ◽  
Joining Technology ◽  
Isotropic Conductive Adhesives

A new hybrid soldering and conductive adhesive joining technology using a fusible lowmelting- point alloy (LMPA) have been developed. A numerical method for numerical analysis of fusible particles behavior is proposed to investigate coalescence characteristics of fusible particles in solderable isotropic conductive adhesives (ICAs). For finding out suitable conditions to obtain reliable conduction paths, the present study examines the influence of process-related parameters such as volume fraction and viscosity on coalescence characteristics of fusible particles.

Recent progress in flapping wings for micro aerial vehicle applications

2020 ◽  
pp. 095440622091742
Author(s):  
Naeem Haider ◽  
Aamer Shahzad ◽  
Muhammad Nafees Mumtaz Qadri ◽  
Syed Irtiza Ali Shah
Keyword(s):  
Leading Edge ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Structural Flexibility ◽  
Micro Aerial Vehicles ◽  
Flexible Wings ◽  
Performance Variables ◽  
Aerial Vehicles ◽  
Wide Range ◽  
Wing Geometry

Micro aerial vehicles using flapping wings are under investigation, as an alternative to fixed-wing and rotary-wing micro aerial vehicles. Such flapping-wing vehicles promise key potential advantages of high thrust, agility, and maneuverability, and have a wide range of applications. These applications include both military and commercial domains such as communication relay, search and rescue, visual reconnaissance, and field search. With the advancement in the computational sciences, developments in flapping-wing micro aerial vehicles have progressed exponentially. Such developments require a careful aerodynamic and aeroelastic design of the flapping wing. Therefore, aerodynamic tools are required to study such designs and configurations. In this paper, the role of several parameters is investigated, including the types of flapping wings, the effect of the kinematics and wing geometry (shape, configuration, and structural flexibility) on performance variables such as lift, drag, thrust, and efficiency in various modes of flight. Kinematic variables have a significant effect on the performance of the flapping wing. For instance, a high flap amplitude and pitch rotation, which supports the generation of the strong leading-edge vortex, generates higher thrust. Likewise, wing shape, configuration, and structural flexibility are shown to have a large impact on the performance of the flapping wing. The wing with optimum flexibility maximizes thrust where highly flexible wings lead to performance degradation due to change in the effective angle of attack. This study shows that the development of the flexible flapping wing with performance capabilities similar to those of natural fliers has not yet been achieved. Finally, opportunities for additional research in this field are recommended.

Induced Strain Actuation for Solid-State Ornithopters: An Aeroelastic Study

2018 ◽  
Author(s):  
Francis Hauris ◽  
Onur Bilgen
Keyword(s):  
Reynolds Number ◽  
Solid State ◽  
Aspect Ratio ◽  
Interaction Model ◽  
Flapping Wing ◽  
Flapping Wings ◽  
Structural Behavior ◽  
Structure Interaction ◽  
Dynamic Motion ◽  
Lift And Drag

This paper investigates the dynamic aeroelastic behavior of strain actuated flapping wings with various geometries and boundary conditions. A fluid-structure interaction model of a plate-like flapping wing is developed. Assuming a chord Reynolds number of 100,000, the wing is harmonically actuated while varying parameters such as aspect ratio and wing root clamped percentage. Characteristic metrics for the dynamic motion, natural frequency, lift and drag are developed. These results are compared with purely structural behavior to understand the aeroelastic effects.

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