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Role on Moment of Inertia and Vortex Dynamics for a Thin Rotating Plate  [PDF]
Yoshihiro Kubota, Osamu Mochizuki
World Journal of Mechanics (WJM) , 2013, DOI: 10.4236/wjm.2013.36028
Abstract:

In this study, we focused on the lift generation with a thin rotating plate. The objective of this study is to understand the appropriate shape and the role of vortex for rotating thin plate. We determined the shape of the plate through free-flight tests of paper strips and investigated the aerodynamic characteristics of the rotating plate with the selected shape. The rectangular plate with an aspect ratio 7 was relevant from moment of inertia and bending stress. An endplate on a wing tip increased the stability on the lateral vortex structure behind the rotating plate. Velocity field measurement by Particle Image Velocimetry (PIV) showed that the lift force was generated twice in a rotating cycle.

Investigation of acoustic field near to elastic thin plate using integral method Исследование акустического поля около упругой тонкой панели с использованием интегрального метода ДОСЛ ДЖЕННЯ АКУСТИЧНОГО ПОЛЯ Б ЛЯ ПРУЖНО ТОНКО ПАНЕЛ З ВИКОРИСТАННЯМ НТЕГРАЛЬНОГО МЕТОДУ  [cached]
В.?. Токарев,О.?. Запорожець
Proceedings of National Aviation University , 2004,
Abstract: Investigation of acoustic field near to elastic thin plate using integral method The influence of boundary conditions on sound wave propagation, radiation and transmission through thin elastic plate is investigated. Necessary for that numerical model was found using the Helmholtz equation and equation of oscilated plate by means of integral formulation of the solution for acoustic fields near to elastic thin plate and for bending waves of small amplitudes. Исследовано влияние граничных условий на распространение, излучение и прохождение акустических волн сквозь тонкую эластическую панель. Решения получены с использованием уравнения Гельмгольца, уравнения колебания тонкой упругой пластины, интегрального метода для акустических полей около упругой тонкой панели и распространения изгибных волн малой амплитуды. Выполнено сравнение полученных результатов с данными экспериментальных исследований. Досл джено вплив граничних умов на розповсюдження, випром нювання проходження акус- тичних хвиль кр зь тонку еластичну панель. Обчислювальну модель отримано з використанням р вняння Гельмгольца та р вняння коливання пластини на основ нтегрального методу для акустичних пол в б ля пружно тонко панел та поширення згинних хвиль малих ампл туд.
半转翼悬停状态下气动特性实验研究
Experimental Investigation of Aerodynamic Characteristics for Half-rotating Wing in Hovering Flight
 [PDF]

王孝义,邓家国,李倩,张玉华,邱支振
- , 2018,
Abstract: 半转翼是一种以转动式扑动替代摆动式扑动的新型类扑翼仿生飞行系统。为了探索半转翼悬停状态下气动特性影响规律,在介绍半转翼工作原理的基础上,给出了升力测试装置方案及其测试计算模型,分别从翼片布局、翼片材料特性对气动特性的影响展开实验研究。实验结果表明:左右对称布置的翼片运动后产生的流场相互干扰,导致双翼式半转翼平均升力系数小于单翼式半转翼;柔性翼片平均升力系数一般比刚性翼片大;在合适松弛度范围内,柔性翼片平均升力随松弛度增加而增大。研究结果揭示了半转翼悬停状态下的气动特性。
Half-rotating wing (HRW) is a new flapping-imitating wing system with rotating-type flapping instead of oscillating-type flapping. The working principle of HRW was firstly introduced in this paper. The design scheme of lift testing device and lift computational model were then given to explore the aerodynamic characteristics of HRW in hovering flight. The aerodynamic experiment was performed by two wing layout with different wing material. The experiment results showed that:the flow field generated by the motion of the wing arranged symmetry in body would interfere with each other, by which the average lift coefficient of the double-wing HRW was less than that of the single-wing HRW;on the other hand, the average lift coefficient of flexible wing was larger than that of the rigid wing;in addition, the average lift of the flexible wing would go up with the increasing of degree of relaxation when it was within the appropriate range. Above research results revealed the aerodynamic characteristics of HRW in hovering flight
Investigation of surface integrity in high-speed ball end milling of cantilever shaped thin plate of Inconel 718  [PDF]
N.N. Bhopale,R.S. Pawade
Journal of Achievements in Materials and Manufacturing Engineering , 2012,
Abstract: The paper addresses the effects of cutting speed and feed on the work piece deflection and surface integrity during milling of cantilever shaped Inconel 718 plate under different cutter orientations. The experiments were conducted on a CNC vertical milling machine using 10 mm diameter TiAlN coated solid carbide ball end milling cutter. Surface integrity is assessed in terms of micro hardness beneath the machined surface. The micro-hardness profile shows different patterns at various cutting parameters. It is observed that at large cutting speed as well as feeds, thicker work piece with larger work piece inclination shows higher micro hardness as compared to the other machining conditions.
Wind Tunnel Experimental Investigation on Aerodynamic Characteristics of Non-Parachute Terminal Sensitive Ammunition
无伞末敏弹气动特性风洞实验研究

ZHOU Zhi-Chao,ZHAO Run-Xiang,HAN Zi-Peng,TAO Gang,
周志超
,赵润祥,韩子鹏,陶钢

实验力学 , 2012,
Abstract: A kind of projectile's aerodynamic configuration with short cylinder and axial asymmetric tail wings was designed. High angle of attack low speed wind tunnel experiment was carried out based on self-designed specimen model and experimental equipment. Aerodynamic force of model with or without rotating damping wing was obtained under being fixed or free rotating conditions. The rotate speed of model affected by aerodynamic force was also measured. Results show that the designed tail wings can provide large drag force for model, while the drag coefficient of model becomes smaller during rotating. The model with rotating damping wing can keep low stable spin rate. Model has bad static stability, but the stability is improved greatly when it is rotating. In order to improve the static stability of model and to guarantee the stability of the scanning angle, the tail wing shape needs to be optimized. Above mentioned investigation may provide reference for non-parachute TSA design and improvement.
Aerodynamic Performance Analysis of A Flat plate Hawt  [PDF]
Prof. Bavanish. B,Dr. Thyagarajan. K
International Journal of Recent Technology and Engineering , 2012,
Abstract: Composite material design has almost become routinedue to the palpable advantages like considerable weight savingand opportunity to adapt the structure to the given set of designrequirements. Pollution free electricity generation, lowoperation and maintenance costs, quick installation,commissioning capability, free renewable energy are the addedadvantages of wind electric generators. This paper alsoaddresses the design parameters of composite wind turbineblades. The key factors for proper utilization of wind power anddesigning wind energy conversion systems are the performancecharacteristics of available wind energy conversion system andthe availability of wind resources. The performancecharacteristics depend on the aerodynamic, mechanical andelectrical subsystems whereas the wind resources depend on theweather conditions of the region. The goal in designing a windturbine is to attain highest possible output under specifiedatmospheric conditions and profit from better structural modelusing suitable composite material and optimization techniquesin manufacturing. Determining optimal shape of the blade andoptimal composite material is complex one, as the mathematicaldescription of aerodynamic load is complex and it should satisfyboth the constraints and objectives of the problem. This paperincorporates the performance and design aspects, sitingrequirements, classification of wind electric conversion systems,choice of rotors and generators, environmental aspects andoptimization concepts of wind turbine rotors.
Unsteady Couette Flow through a Porous Medium in a Rotating System  [PDF]
Maitree Jana, Sanatan Das, Rabindra Nath Jana
Open Journal of Fluid Dynamics (OJFD) , 2012, DOI: 10.4236/ojfd.2012.24016
Abstract: An investigation has been made on an unsteady Couette flow of a viscous incompressible fluid through a porous me- dium in a rotating system. The solution of the governing equations has been obtained by the use of Laplace transform technique. It is found that the primary velocity decreases and the magnitude of the secondary velocity increases with an increase in rotation parameter. The fluid velocity components are decelerated by an increase of Reynolds number. An increase in porosity parameter leads to increase the primary velocity and the magnitude of the secondary velocity. It is also found that the solution for small time converges more rapidly than the general solution. The asymptotic behavior of the solution is analyzed for small as well as large values of rotation parameter and Reynolds number. It is observed that a thin boundary layer is formed near the moving plate of the channel and the thicknesses of the boundary layer increases with an increase in porosity parameter.
Transfinite thin plate spline interpolation  [PDF]
Aurelian Bejancu
Mathematics , 2009, DOI: 10.1007/s00365-010-9118-3
Abstract: Duchon's method of thin plate splines defines a polyharmonic interpolant to scattered data values as the minimizer of a certain integral functional. For transfinite interpolation, i.e. interpolation of continuous data prescribed on curves or hypersurfaces, Kounchev has developed the method of polysplines, which are piecewise polyharmonic functions of fixed smoothness across the given hypersurfaces and satisfy some boundary conditions. Recently, Bejancu has introduced boundary conditions of Beppo Levi type to construct a semi-cardinal model for polyspline interpolation to data on an infinite set of parallel hyperplanes. The present paper proves that, for periodic data on a finite set of parallel hyperplanes, the polyspline interpolant satisfying Beppo Levi boundary conditions is in fact a thin plate spline, i.e. it minimizes a Duchon type functional.
An elastic plate on a thin viscous film  [PDF]
Philippe H. Trinh,Stephen K. Wilson,Howard A. Stone
Physics , 2014,
Abstract: We consider the steady-state analysis of a pinned elastic plate lying on the free surface of a thin viscous fluid, forced by the motion of a bottom substrate moving at constant speed. A mathematical model incorporating elasticity, viscosity, surface tension, and pressure forces is derived, and consists of a third-order Landau-Levich equation for the thin film, and a fifth-order beam equation for the plate. A numerical and asymptotic analysis is presented in the relevant limits of the elasticity and Capillary numbers. We demonstrate the emergence of boundary-layer effects near the ends of the plate, which are likely to be a generic phenomenon for singularly perturbed elastocapillary problems.
Rotating Relativistic Thin Disks  [PDF]
Guillermo A. González,Patricio S. Letelier
Physics , 2000, DOI: 10.1103/PhysRevD.62.064025
Abstract: Two families of models of rotating relativistic disks based on Taub-NUT and Kerr metrics are constructed using the well-known "displace, cut and reflect" method. We find that for disks built from a generic stationary axially symmetric metric the "sound velocity", $(pressure/density)^{1/2}$, is equal to the geometric mean of the prograde and retrograde geodesic circular velocities of test particles moving on the disk. We also found that for generic disks we can have zones with heat flow. For the two families of models studied the boundaries that separate the zones with and without heat flow are not stable against radial perturbations (ring formation).
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