scholarly journals Morphic Arrangement of High Flexibility and Aspect Ratio Wing

2020 ◽  
Author(s):  
Wojciech Skarka ◽  
Nikodem Ciomperlik
Keyword(s):  
Aspect Ratio ◽  
High Altitude ◽  
High Aspect Ratio ◽  
Shape Adaptation ◽  
Wide Range ◽  
High Flexibility ◽  
Conventional Solution ◽  
Actuation Devices ◽  
Long Endurance ◽  
Aerodynamic Surfaces

Morphing of aerodynamic surfaces or conformal shape adaptation of aerodynamic surfaces can be used to control aircraft, utilized similarly as in nature, where insects and birds deform their wings to achieve a wide range of flight conditions. Morphing of wings has the potential to bring numerous advantages in flight performance in comparison to a rigid, conventional solution, that utilizes stiff aerodynamic surfaces. Reduction of parasitic drag due to the lack of gaps between the various moveable surfaces is one of them. Even so, a wing whose sections are able to deform independently or conform can better adapt to wide range of flight conditions than a rigid solution, or a solution based on conventional aerodynamic surfaces, such as flaps and ailerons. Additionally, the conformal shape adaptation or morphing of aerodynamic surfaces may lead to a potentially reduced weight and mechanical complexity, which may be achieved by utilizing wing deformations directly in the structure instead of connecting conventional actuation devices to the system. The aim of this paper is to propose a morphic arrangement of a high flexibility and high aspect ratio wing, that could be utilized in High Altitude Long Endurance aircraft, where the efficiency of the design is of utmost importance. A significant reduction of parasitic drag and reduction of weight is a promising basis for pursuing morphic and conformal shape adaptation designs. This paper qualitatively explores the space of morphic arrangements and conformal shape adaptation designs and utilizes inventive approaches to check and identify designs that may be promising. A wing design is proposed, that utilizes morphing of wing and conformal shape adaptation.

scholarly journals High-resolution particle separation by inertial focusing in high aspect ratio curved microfluidics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Javier Cruz ◽  
Klas Hjort
Keyword(s):  
High Resolution ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Biological Fluids ◽  
Essential Feature ◽  
Particle Separation ◽  
Size Difference ◽  
Inertial Focusing ◽  
Complex Samples ◽  
Wide Range

AbstractThe ability to focus, separate and concentrate specific targets in a fluid is essential for the analysis of complex samples such as biological fluids, where a myriad of different particles may be present. Inertial focusing is a very promising technology for such tasks, and specially a recently presented variant, inertial focusing in High Aspect Ratio Curved systems (HARC systems), where the systems are easily engineered and focus the targets together in a stable position over a wide range of particle sizes and flow rates. However, although convenient for laser interrogation and concentration, by focusing all particles together, HARC systems lose an essential feature of inertial focusing: the possibility of particle separation by size. Within this work, we report that HARC systems not only do have the capacity to separate particles but can do so with extremely high resolution, which we demonstrate for particles with a size difference down to 80 nm. In addition to the concept for particle separation, a model considering the main flow, the secondary flow and a simplified expression for the lift force in HARC microchannels was developed and proven accurate for the prediction of the performance of the systems. The concept was also demonstrated experimentally with three different sub-micron particles (0.79, 0.92 and 1.0 µm in diameter) in silicon-glass microchannels, where the resolution in the separation could be modulated by the radius of the channel. With the capacity to focus sub-micron particles and to separate them with high resolution, we believe that inertial focusing in HARC systems is a technology with the potential to facilitate the analysis of complex fluid samples containing bioparticles like bacteria, viruses or eukaryotic organelles.

scholarly journals Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 80
Author(s):  
Dmitry V. Vedernikov ◽  
Alexander N. Shanygin ◽  
Yury S. Mirgorodsky ◽  
Mikhail D. Levchenkov
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Performance ◽  
Strength Analysis ◽  
Labor Input ◽  
Aerodynamic Loading ◽  
Aspect Ratios ◽  
Wide Range ◽  
Parametrical Design

This publication presents the results of complex parametrical strength investigations of typical wings for regional aircrafts obtained by means of the new version of the four-level algorithm (FLA) with the modified module responsible for the analysis of aerodynamic loading. This version of FLA, as well as a base one, is focused on significant decreasing time and labor input of a complex strength analysis of airframes by using simultaneously different principles of decomposition. The base version includes four-level decomposition of airframe and decomposition of strength tasks. The new one realizes additional decomposition of alternative variants of load cases during the process of determination of critical load cases. Such an algorithm is very suitable for strength analysis and designing airframes of regional aircrafts having a wide range of aerodynamic concepts. Results of validation of the new version of FLA for a high-aspect-ratio wing obtained in this work confirmed high performance of the algorithm in decreasing time and labor input of strength analysis of airframes at the preliminary stages of designing. During parametrical design investigation, some interesting results for strut-braced wings having high aspect ratios were obtained.

scholarly journals Self-ordered nanospike porous alumina fabricated under a new regime by an anodizing process in alkaline media

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mana Iwai ◽  
Tatsuya Kikuchi ◽  
Ryosuke O. Suzuki
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Porous Alumina ◽  
Three Dimensional ◽  
Alkaline Media ◽  
Alkaline Electrolyte ◽  
Subsequent Formation ◽  
Interpore Distance ◽  
Wide Range ◽  
Ordered Porous

AbstractHigh-aspect ratio ordered nanomaterial arrays exhibit several unique physicochemical and optical properties. Porous anodic aluminum oxide (AAO) is one of the most typical ordered porous structures and can be easily fabricated by applying an electrochemical anodizing process to Al. However, the dimensional and structural controllability of conventional porous AAOs is limited to a narrow range because there are only a few electrolytes that work in this process. Here, we provide a novel anodizing method using an alkaline electrolyte, sodium tetraborate (Na2B4O7), for the fabrication of a high-aspect ratio, self-ordered nanospike porous AAO structure. This self-ordered porous AAO structure possesses a wide range of the interpore distance under a new anodizing regime, and highly ordered porous AAO structures can be fabricated using pre-nanotexturing of Al. The vertical pore walls of porous AAOs have unique nanospikes measuring several tens of nanometers in periodicity, and we demonstrate that AAO can be used as a template for the fabrication of nanomaterials with a large surface area. We also reveal that stable anodizing without the occurrence of oxide burning and the subsequent formation of uniform self-ordered AAO structures can be achieved on complicated three-dimensional substrates.

The Effect of Structural Geometric Nonlinearities on the Flutter of the Straight and Swept Wing Configurations

2012 ◽  
Vol 189 ◽  
pp. 306-311 ◽  
Author(s):  
Qing Guo ◽  
Bi Feng Song
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Swept Wing ◽  
Geometric Nonlinearities ◽  
Air Vehicle ◽  
Structural Nonlinearity ◽  
Flutter Analysis ◽  
Long Endurance ◽  
The Impact ◽  
Straight Wing

High altitude and long endurance (HALE) vehicle always adopt straight or swept configuration, which leads to the problem that the wings of UAV have high aspect ratio and are very flexible. This kind of flexible wing exhibits large deformation when aerodynamic forces are loaded on them and the structural nonlinearity should be considered. So the dynamic and flutter characteristics will be changed. In the engineering applications, the effects of structural geometric nonlinearities on the air vehicle design are the most concerns of aeroelasticity before a systematic flutter analysis for the air vehicle. because the solution for nonlinear flutter speed based on the CFD-CSD method is complex and time consuming. In this paper, we propose a simple and efficient approach that can analyze the effect of structural geometric nonlinearities on the flutter characteristics of high aspect ratio wing quickly. And a straight wing and a straight-swept wing are analyzed to verify the feasibility and efficiency of the proposed method. It is found that the effect of structural geometric nonlinearities has a strong effect on the flutter characteristic of the straight wing, but is weak on the straight-swept wing. And finally the impact of swept angle on the dynamic and flutter characteristics of straight-swept wing is also discussed.

Effects of Tail Geometries on the Performance and Wake Pattern in Flapping Propulsion

2016 ◽  
Author(s):  
Geng Liu ◽  
Haibo Dong
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Computational Study ◽  
Hydrodynamic Performance ◽  
Immersed Boundary ◽  
Caudal Fin ◽  
Flow Solver ◽  
Wide Range ◽  
Wake Patterns ◽  
Caudal Fin Shape

Swimming fishes exhibit remarkable diversities of the caudal fin geometries. In this work, a computational study is conducted to investigate the effects of the caudal fin shape on the hydrodynamic performance and wake patterns in flapping propulsion. We construct the propulsor models in different shapes by digitizing the real caudal fins of fish across a wide range of species spanning homocercal tails with low aspect ratio (square shape used by bluegill sunfish, rainbow trout, etc.) or high aspect ratio (lunate shape adopted by tuna, swordfish, etc.), and even heterocercal caudal fin adopted by sharks. Those fin models perform the same flapping motion in a uniform flow to mimic fish’s forward swimming. We then simulate the flow around the flapping fins by an in-house immersed-boundary-method based flow solver. According to the analysis of the hydrodynamic performance, we have found that the lunate shape model (high aspect-ratio) always generates a larger thrust compared to other models. The comparison of the propulsive efficiency shows that the large aspect ratio fins (tuna and shark) have a higher efficiency when the Strouhal number (St) is in the range of steady swimming (0.2<St<0.4), while the lower aspect ratio caudal fins (catfish, trout, etc.) are more efficient when St>0.4, in which the fish is accelerating or maneuvering. Finally, the 3D wake patterns of those propulsors are analyzed in detail.

scholarly journals Scalable Production of Monodisperse Functional Microspheres by Multilayer Parallelization of High Aspect Ratio Microfluidic Channels

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 592 ◽  
Author(s):  
Casper Ho Yin Chung ◽  
Binbin Cui ◽  
Ruyuan Song ◽  
Xin Liu ◽  
Xiaonan Xu ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Large Scale ◽  
Scale Up ◽  
Functional Materials ◽  
Droplet Microfluidics ◽  
Microfluidic Channels ◽  
Layer By Layer ◽  
Precise Control ◽  
Wide Range

Droplet microfluidics enables the generation of highly uniform emulsions with excellent stability, precise control over droplet volume, and morphology, which offer superior platforms over conventional technologies for material synthesis and biological assays. However, it remains a challenge to scale up the production of the microfluidic devices due to their complicated geometry and long-term reliability. In this study, we present a high-throughput droplet generator by parallelization of high aspect ratio rectangular structures, which enables facile and scalable generation of uniform droplets without the need to precisely control external flow conditions. A multilayer device is formed by stacking layer-by-layer of the polydimethylsiloxane (PDMS) replica patterned with parallelized generators. By feeding the sample fluid into the device immersed in the carrying fluid, we used the multilayer device with 1200 parallelized generators to generate monodisperse droplets (~45 μm in diameter with a coefficient of variation <3%) at a frequency of 25 kHz. We demonstrate this approach is versatile for a wide range of materials by synthesis of polyacrylamide hydrogel and Poly (l-lactide-co-glycolide) (PLGA) through water-in-oil (W/O) and oil-in-water (O/W) emulsion templates, respectively. The combined scalability and robustness of such droplet emulsion technology is promising for production of monodisperse functional materials for large-scale applications.

Analysis on Flight Dynamics of Solar UAV with Multiple Propulsion Systems

2011 ◽  
Vol 138-139 ◽  
pp. 453-458 ◽  
Author(s):  
Wei Xiao ◽  
Zhou Zhou
Keyword(s):  
Aspect Ratio ◽  
High Altitude ◽  
Flight Dynamics ◽  
System Efficiency ◽  
Large Aspect Ratio ◽  
Propulsion Systems ◽  
Obvious Effect ◽  
Modified Model ◽  
Distributed Propulsion ◽  
Long Endurance

High Altitude Long Endurance (HALE) Solar UAV is integrated with a series of motor-propeller propulsion systems along the large aspect-ratio wing. These systems have an obvious effect on the flight dynamics of the UAV. This paper established a model for the interaction between distributed propulsion systems and the flight dynamics of the airplane, it was used to improve the computation of the UAV’s flight quality, results with and without the modified model were compared. It was found that the large aspect-ratio wing integrated with distributed propulsion systems can change its stability significantly. According to the result, parameters of the propulsion systems are adjusted to optimize the flight quality and system efficiency.

Functional Texture Design and Texturing Processes

2016 ◽  
Vol 10 (1) ◽  
pp. 4-15 ◽  
Author(s):  
Nobuyuki Moronuki ◽  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Cross Sectional ◽  
Nano Structure ◽  
Wide Range ◽  
The Hierarchical Structure ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Texture Design ◽  
Regular Patterns

Various functions can be obtained by applying regular patterns or textures to surfaces. Depending on the function, the required dimensions of the texture, such as the pitch, vary over a wide range: from nanometers for optical function to millimeters for friction. In addition, the high aspect ratio of the cross sectional profile or the hierarchical structure of a micro- or nano-structure is required to control the wettability, for example. This paper reviews various texturing processes as well as the functionalities thus attained and their application.

HALE UAV Composite Wing Structure Design

2010 ◽  
Vol 123-125 ◽  
pp. 105-108
Author(s):  
Myoung Keon Lee ◽  
Chang Min Cho ◽  
Se Yong Jang
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Composite Structure ◽  
Buckling Analysis ◽  
Design Parameters ◽  
Critical Design ◽  
Design Requirements ◽  
Wing Structure ◽  
Long Endurance ◽  
Composite Wing

HALE (High Altitude Long Endurance) UAVs are aircraft systems for surveillance and reconnaissance for over 25 hours. Most of UAVs consist of fuselage and high aspect ratio wing because of long-endurance flight mission. The structural weight of HALE UAV is one of the most critical design requirements. In addition, the structural stiffness for the high aspect ratio wing is another critical design requirement because the UAV has to keep the minimum clearance between wing tip and ground when the UAV is being towed. For above design requirements, the wing structure of the UAV has been designed by intermediate modulus Gr/Ep composite materials. The goal of this research is to present the optimized design concepts for the composite wing structure of the UAV. Although there are many design parameters for the composite structure of the aircraft, this research is focused on composite structure strength and buckling analysis for the plate type structures, such as cover panel skins and spar webs, which are loaded in in-plane shear and/or compression. This research presents that the wing structural weight can be reduced when the material allowables based on tape laminate are applied instead of unidirectional lamina allowables. For the buckling analysis, this report has a trade off study to find an optimized lay-up design and stacking sequence with 0°, ±45° and 90° plies. This research shows that the critical buckling load is a function of the number of ±45° plies and the position of the ±45° plies through the laminate thickness using a typical Gr/Ep composite tape material. The structural design of the UAV composite wing regarding buckling analysis is more effective when the laminates are stacked up with high percent of ±45° plies and the ±45° plies are located toward outside through the laminate.

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