المؤلفون: Balbir Singh, Noorfaizal Yidris, Adi Azriff Basri, Radhika M. Pai, Kamarul Arifin Ahmad

مصطلحات موضوعية: Lattice Boltzmann Method for Complex Flows, Computational Mechanics, Engineering, Physical Sciences, Turbulent Flows and Vortex Dynamics, Vortex-Induced Vibrations in Fluid Flow, Lattice Boltzmann Method, Aerodynamic Characteristics, Lattice Boltzmann methods, Reynolds number, Wing, Aerodynamics, Chord peer-to-peer, Mechanics, Computational fluid dynamics, Vortex, Solver, Parametric statistics, Physics, Geometry, Classical mechanics, Mathematics, FOS Mathematics, Structural engineering, Computer science, Mathematical optimization, Turbulence, Distributed computing, Statistics

الوصف: During the course of recent studies on wings at low Reynold number, it was observed that wing corrugation is often assumed to play an important role as well. However, studies show that corrugation of the wing is intended for structural purposes, and not aerodynamics. Corrugated wings have the advantage of being light and sturdy. Therefore, the main aim of this study is to understand the flow behaviour of the corrugated insect-scale wing; by conducting, a geometric parametric study during a non-oscillatory flight at a particular low Reynolds number and at two different angles of attack. In this computational study, a 3-D section of the corrugated wing along the chord is considered. The lattice Boltzmann method offers an alternative framework compared to the Navier-Stokes simulations. An open-source Parallel Lattice Boltzmann Solver on a high-performance computing platform is used for this computational analysis. The present study shows that the flow-related performance of the corrugated wing in terms of ... : خلال الدراسات الأخيرة على الأجنحة ذات عدد رينولد المنخفض، لوحظ أن تموج الجناح غالبًا ما يُفترض أنه يلعب دورًا مهمًا أيضًا. ومع ذلك، تشير الدراسات إلى أن تموج الجناح مخصص للأغراض الهيكلية، وليس للديناميكا الهوائية. تتميز الأجنحة المموجة بأنها خفيفة وقوية. لذلك، فإن الهدف الرئيسي من هذه الدراسة هو فهم سلوك تدفق الجناح المموج على نطاق الحشرات ؛ من خلال إجراء دراسة هندسية بارامترية أثناء رحلة غير متذبذبة عند رقم رينولدز منخفض معين وعند زاويتي هجوم مختلفتين. في هذه الدراسة الحسابية، يتم النظر في قسم ثلاثي الأبعاد من الجناح المموج على طول الوتر. توفر طريقة بولتزمان الشبكية إطارًا بديلًا مقارنةً بمحاكاة Navier - Stokes. يتم استخدام Parallel Lattice Boltzmann Solver مفتوح المصدر على منصة حوسبة عالية الأداء لهذا التحليل الحسابي. تظهر الدراسة الحالية أن الأداء المرتبط بالتدفق للجناح المموج من حيث القوى والطاقة الحركية تحكمه في الغالب الاختلافات الهندسية التي يمكن أن تؤثر إلى حد كبير على تكوين الدوامات وتفاعلها المتبادل. تكشف الدراسة أن وجود التموج لا يؤثر على تعزيز القوى والتموج بالقرب من الحافة الأمامية يؤثر بشكل عام ...

العلاقة: https://dx.doi.org/10.60692/1dtym-8eq32Test

الإتاحة: https://doi.org/10.60692/qw37d-9jy5910.60692/1dtym-8eq32Test

المؤلفون: Naderinezhad, Mahdi, Djavareshkian, M.H.

المصدر: Aircraft Engineering and Aerospace Technology, 2022, Vol. 95, Issue 4, pp. 512-524.

الوصول الحر: http://www.emeraldinsight.com/doi/10.1108/AEAT-03-2022-0089Test

المؤلفون: Martins, Daniel Filipe Teixeira

المساهمون: Correia, João Patrício Soares, Silva, André Resende Rodrigues da, uBibliorum

مصطلحات موضوعية: Ground Effect, Aerodynamics, Breakdown, Computational Fluid Dynamics, Detached Eddy Simulation, Formula One, Numerical Study, Spalart-Allmaras, Transient Flow, Turbulence, Unsteady, Vortex, Wheel, Wing, Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica

الوصف: The present study focuses on investigating the aerodynamical interaction between a threeelement wing and wheel in ground effect, regarding the Formula One regulations change set for 2022 - amongst the changes is the declutter of the front wing, consequently reducing its complexity. This was accomplished by conducting a three-dimensional computational analysis, using a Detached Eddy Simulation approach, on a simplified one-quarter CAD model, built from the ground up following the regulations imposed by the FIA. The main goal was to examine how changing the front wing pressure distribution affected wheel aerodynamics, which will then influence the feeding process of the underbody, due to their proximity and subsequent flow interaction. This was done by varying the angle of attack of the second flap on the wing. The CFD study was divided into two sections: a flow analysis and a force analysis. On the flow analysis, one focused on determining the location and intensity of flow energy losses; visualizing the flow structures around the wing and wheel; and, where possible, identifying and comprehending the mechanisms behind the observed flow phenomena. On the force analysis, the transient variations of the force coefficients were examined to better understand how the unsteadiness of the vortices influenced the wing’s performance. The flow investigation indicated that the wheel wake structure is significantly influenced by the wing’s flap configuration, showing different shapes to the different geometries tested. This is mainly due to the fact that different flap configurations produce different upwash flow fields, leading to a separation point variation on top of the wheel. This variation then affects the downwash observed behind the central region of the wheel, for a vertical plane. The force investigation showed that the location of the region of instability influences the behaviour of the transient oscillations, regarding the forces acting on the wing: bearing in mind that vortex breakdown occurs near the wing’s trailing edge, higher drag force fluctuations are detected, when compared to downforce fluctuations – a shared pattern across the geometries tested.

وصف الملف: application/pdf

الإتاحة: http://hdl.handle.net/10400.6/11677Test

المؤلفون: Patil Manthan, Gawade Rajesh, Potdar Shubham, Nadaf Khushabu, Suresh Sanoj P., Sahoo Devabrata

المصدر: FME Transactions, Vol 49, Iss 2, Pp 395-400 (2021)

مصطلحات موضوعية: subsonic, lift, drag, vortex, delta wing, Engineering (General). Civil engineering (General), TA1-2040, Mechanics of engineering. Applied mechanics, TA349-359

الوصف: Flow over a conventional delta wing has been studied experimentally at a subsonic flow of 20 m/sec and the flow field developed at higher angle of attack varying from 10° to 20° has been captured. A vortex generator is mounted on the leeward surface of the delta wing and its effect on the flow field is studied. The set of wing tip vortices generated over the delta wing is captured by the oil flow visualization and the streamline over the delta wing surface captured with and without a vortex generator are compared. Based on the qualitative results, the effect of the vortex generator on the lift coefficient is anticipated. Further, force measurement is carried out to quantitatively analyze the effect of vortex generator on the lift and drag coefficient experienced by the delta wing and justify the anticipation made out of the qualitative oil flow visualization tests. In the present study, the effect of mounting of a vortex generator is found to be minimal on the lift coefficient experienced by the delta wing. However, a significant reduction in the drag coefficient with increase in angle of attack was observed by mounting a typical vortex generator.

وصف الملف: electronic resource

العلاقة: https://scindeks-clanci.ceon.rs/data/pdf/1451-2092/2021/1451-20922102395P.pdfTest; https://doaj.org/toc/1451-2092Test; https://doaj.org/toc/2406-128XTest

الوصول الحر: https://doaj.org/article/6de8e69861144dca83fcc0017d667732Test

المؤلفون: Davari, Ali R.¹ ardavari@srbiau.ac.ir

المصدر: Aerospace Science & Technology. Apr2018, Vol. 75, p88-98. 11p.

مصطلحات موضوعية: *AIRPLANE wing testing, *ACTUATOR testing, *SUBSONIC flow, *RESPONSE surfaces (Statistics), *AEROSPACE technology, *REGRESSION analysis

مستخلص: A new approach is presented based on Response Surface Method to estimate the tail normal force in the immediate vicinity of a low aspect ratio swept wing by a simple analytical model in subsonic flow regime. Apart from the inevitable role of the tail in aircraft static stability, the force on the tail is needed for structural design process and also to select the proper actuator mechanism to deflect it in both on-design and off-design flight conditions. Several wind tunnel tests have been performed to obtain a physical insight into the impact of wing on the tail flow filed and to identify the independent factors responsible for this interaction. In these experiments, various wing palnforms were placed closely upstream of a tail. Many combinations of body angle of attack and tail deflections have been examined and the tail flow field was studied for each wing by measuring the tail pressure distribution on its either sides. The response surface was constructed using these experimental results and several comparisons were made between the experimental data and those predicted by the proposed model. Remarkable agreement was achieved for the total angles below the one corresponding to vortex burst and flow separation on the tail surface. For any cases, far out of the ranges considered in this paper, the model needs to be corrected to account for the flow phenomena associated with the new ranges of the variables. [ABSTRACT FROM AUTHOR]

المؤلفون: Hao Li, Mostafa R. A. Nabawy

مصطلحات موضوعية: Biological and Biomimetic Flight Dynamics, Aerospace Engineering, FOS Mechanical engineering, Engineering, Physical Sciences, Turbulent Flows and Vortex Dynamics, Computational Mechanics, Vortex-Induced Vibrations in Fluid Flow, Flight Dynamics, Aerodynamic Characteristics, Wake, Lift data mining, Mechanics, Physics, Vortex, Trailing edge, Wing, Aerodynamics, Leading edge, Reynolds number, Aerospace engineering, Computer science, Turbulence, Data mining

الوصف: A wing generating lift leaves behind a region of disturbed air in the form of a wake. For a hovering insect, the wings must return through the wake produced by the previous half-stroke and this can have significant effects on the aerodynamic performance. This paper numerically investigates 2D wings interacting with their own wake at Reynolds numbers of 102and 103, enabling an improved understanding of the underlying physics of the 'wake capture' aerodynamic mechanism of insect flight. We adopt a simple kinematic motion pattern comprised of a translational stroke motion followed by a complete stop to expose wake interaction effects. Representative stroke distance to chord ratios between 1.5 and 6.0 are considered, enabling different leading-edge vortex (LEV) attachment states. We also allow pitching rotation towards the end of stroke, leading to wake intercepting angles of 135°, 90°, and 45°, analogous to delayed, symmetric, and advanced pitching rotations of insect wings. It is shown that both vortex suction ... : المصعد المولّد للجناح يترك وراءه منطقة من الهواء المضطرب في شكل يقظة. بالنسبة للحشرة المحلقة، يجب أن تعود الأجنحة من خلال الاستيقاظ الناتج عن نصف الشوط السابق وهذا يمكن أن يكون له تأثيرات كبيرة على الأداء الديناميكي الهوائي. تبحث هذه الورقة رقميًا في الأجنحة ثنائية الأبعاد التي تتفاعل مع استيقاظها بأعداد رينولدز 102 و 103، مما يتيح فهمًا أفضل للفيزياء الأساسية للآلية الديناميكية الهوائية "لالتقاط الاستيقاظ" لتحليق الحشرات. نعتمد نمط حركة حركية بسيط يتكون من حركة شوط متعدية متبوعة بإيقاف كامل لفضح تأثيرات تفاعل الاستيقاظ. يتم النظر في مسافة السكتة الدماغية التمثيلية إلى نسب الوتر بين 1.5 و 6.0، مما يتيح حالات ربط دوامة الحافة الأمامية المختلفة (LEV). كما نسمح بدوران الميل نحو نهاية الشوط، مما يؤدي إلى استيقاظ زوايا اعتراض 135درجة و 90 درجة و 45درجة، مماثلة للدوران المتأخر والمتماثل والمتقدم لأجنحة الحشرات. لقد تبين أن كلا من آليات الشفط الدوامي وآليات اصطدام التدفق النفاث يمكن أن تؤدي إلى آثار إيجابية أو سلبية اعتمادًا على حالة ارتباط الجهد المنخفض، وأن مسافات السكتة الدماغية التي تؤدي إلى انفصال/ربط الجهد ...

العلاقة: https://dx.doi.org/10.60692/em8rq-4cf18Test

الإتاحة: https://doi.org/10.60692/k7exn-fjk0510.60692/em8rq-4cf18Test

المؤلفون: Dong Xue, Wenqing Yang, Dan Liu, Xinyu Lang, Bifeng Song

المصدر: Chinese Journal of Aeronautics. 35:82-101

مصطلحات موضوعية: Lift (force), Physics, Wing, Mechanical Engineering, Acoustics, Aerospace Engineering, Wing configuration, Flapping, Aerodynamics, Kinematics, Wake, Vortex

الوصف: The slotted wingtip structure of birds is considered to be the product of improving flight efficiency in the process of evolution. It can change the vortex structure of wingtip and improve aerodynamic efficiency. This paper reports a numerical investigation of slotted wing configuration undergoing bio-inspired flapping kinematics (consisting of plunging and in-line movement) extracted from a free-flying bald eagle wing. The aim is to eluci-date the collective mechanism of the flow generated by slotted tips and the lift contribution of each tip. Specifi-cally, the objective of the study is to determine how changes in the wing spacing affect the resulting aerodynamic interaction between the slotted tips and how that affects the force generation and efficiency. Changes in the phase angle between the flapping motions of slotted tips, as well as the spacings among them, can affect the resulting vortex inter-actions. The rear tips often operates in the wake of the frontal tips and, meanwhile, the vortex generated by the movement of the rear tips promote the frontal tips. The interaction of vortices in time and space leads to wing-wing interference and the flow around slotted tips becomes complicated and unstable. The innovative study of wingtip slot in unsteady state leads us to find that the aerodynamic interaction among slotted tips makes the overall lift characteristic better than that of the unslotted wings. The slotted wing configuration can efficiently convert more energy into lift. As the flapping frequency increases, the collective feature of slotted wing with constantly changing gaps can be more advantageous to enhance lift-generation performance.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::63316039f7fbf46d21e8ac437d9e26a0Test
https://doi.org/10.1016/j.cja.2021.07.010Test

المؤلفون: Souaissa, Khaled, Ghiss, Moncef, Chrigui, Mouldi, Bentaher, Hatem, Maalej, Aref

المصدر: Wind Engineering; Oct2019, Vol. 43 Issue 5, p459-475, 17p

مصطلحات موضوعية: VERTICAL axis wind turbines, COMPUTATIONAL fluid dynamics, NAVIER-Stokes equations, ROTORS, WING-warping (Aerodynamics), SHEARING force

مستخلص: Improving the H-Darrieus rotor is often followed by the investigation of the influence of the turbine's parameter design, notably, the aspect ratio, the solidity (σ), the tip speed ratio, and the airfoil profile shape. In this work, we are interested in both the aerodynamic flows around a straight cambered blade profile and the rotor turbine wake separation of a Darrieus vertical axis wind turbine. The aim of this study is to better understand the evolution of the instantaneous torque and the generated-separated blade vortex during full rotation. Indeed, a three-dimensional computational fluid dynamics model of a vertical axis wind turbine with a straight cambered blade profile NACA4312 operating over a large range of tip speed ratio is considered. The flows are governed by Reynolds-averaged Navier–Stokes equations and the turbulence is modeled with shear stress transport formulations k - ω. This research revealed a high correlation between the evolution of the torque coefficient and the generated-separated blades vortex. In particular, a good correlation between the maximum tip vortices size and the torque coefficient peak is demonstrated. [ABSTRACT FROM AUTHOR]

: Copyright of Wind Engineering is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Liu, Tianshu, 王士召, Liu, Hao, 何国威

المساهمون: Liu, Tianshu

مصطلحات موضوعية: Bird, Flight, Scaling, Flapping wing, Airfoil, Wing geometry, Wing kinematics, Aerodynamics, Vortex, Lift, Drag, Thrust, Thin-airfoil theory, Lifting-line theory, Wake models, Kutta-Joukowski theorem, Actuator disk model, Vortex ring model, CFD, Multiple joint arm system, LEADING-EDGE VORTEX, AVIAN WING GEOMETRY, GLIDING FLIGHT, WAKE STRUCTURE, ANIMAL FLIGHT, THRUSH NIGHTINGALE, FLAPPING FLIGHT, ENERGY SAVINGS, FLYING BIRDS, Engineering

الوصف: From the perspective of aeronautical engineers, this paper gives a systematical summary of the technical aspects of bird flight that should be considered in the analysis and design of flapping unmanned and micro air vehicles (UAVs and MAVs). The relevant aspects include the scaling laws, avian wing geometry, avian wing kinematics, aerodynamics models, computations, and special topics. Instead of extensively and uniformly reviewing a wide range of materials studied by avian biologists, we focus on the analytical and semi-analytical models and quantitative data as the useful guidelines for the design of flapping UAVs and MAVs.

العلاقة: PROGRESS IN AEROSPACE SCIENCES; http://dspace.imech.ac.cn/handle/311007/93779Test; http://dspace.imech.ac.cn/handle/311007/93780Test

الإتاحة: https://doi.org/10.1016/j.paerosci.2023.100933Test
http://dspace.imech.ac.cn/handle/311007/93779Test
http://dspace.imech.ac.cn/handle/311007/93780Test

المؤلفون: Ethan B. Loewenthal, Ashok Gopalarathnam

المصدر: AIAA Journal. 60:1708-1720

مصطلحات موضوعية: Physics, Aerodynamic force, Lift coefficient, Flow separation, animal structures, Wing, Horseshoe vortex, Wingtip vortices, Aerospace Engineering, Mechanics, Vortex lattice method, Vortex

الوصف: Wingtip-flow effects on the aerodynamic forces and moments of a wing become increasingly significant as the aspect ratio decreases. These effects are dominated by the tip vortex and an associated s...

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::9c661b62080755e4e9e862c99a0e9e30Test
https://doi.org/10.2514/1.j060654Test