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1
Ferraz, Bruna Fontes, and Claudia Cristina Maia. "Partido: a página virada de Italo Calvino / Partido: Italo Calvino’s Turned Page." O Eixo e a Roda: Revista de Literatura Brasileira 28, no. 3 (2019): 65. http://dx.doi.org/10.17851/2358-9787.28.3.65-82.
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Resumo: Este artigo tem por objetivo apresentar uma análise de Partido, espetáculo teatral do grupo Galpão, de Belo Horizonte, concebido a partir do romance O visconde partido ao meio, de Italo Calvino. Com dramaturgia de Cacá Brandão e direção de Cacá Carvalho, o espetáculo, tratado aqui como uma tradução da obra do escritor italiano, contribuiu para a recepção de Calvino no Brasil. Do texto para o palco, houve um trabalho de transformação que permitiu ao Galpão ir além do livro de Calvino, em alguma medida rompendo com ele. A palavra escrita traduziu-se em uma linguagem que privilegiou o corpo e as experiências de vida dos atores. A tradução foi lida a partir do pensamento de Walter Benjamin, Paul Ricouer e Haroldo de Campos, ressaltando o trabalho do grupo mineiro como uma poética de tradução pautada na produção da diferença.Palavras-chave: O visconde partido ao meio; tradução; teatro; grupo Galpão.Abstract: This paper aims to present an analysis of the play Partido, performed by the theatrical group Galpão, from Belo Horizonte, and conceived from the novel The cloven viscount, by Italo Calvino. With dramaturgy by Cacá Brandão and directed by Cacá Carvalho, the show, perceived here as a translation of Calvino’s work, contributed to the reception of the italian writer in Brazil. From the text to the stage, creators worked on transforming the original text in such a way that allowed Galpão to surpass the book, subverting it in some way. The written word was translated into a language that favored actors’ bodies and life experiences. The translation was analyzed from the thoughts of Walter Benjamin, Paul Ricouer and Haroldo de Campos, highlighting the Minas Gerais group work as a poetic translation based on the production of the different.Keywords: The cloven viscount; translation; theater; Galpão group.
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Beckebanze, F., C. Brouzet, I. N. Sibgatullin, and L. R. M. Maas. "Damping of quasi-two-dimensional internal wave attractors by rigid-wall friction." Journal of Fluid Mechanics 841 (February 26, 2018): 614–35. http://dx.doi.org/10.1017/jfm.2018.107.
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The reflection of internal gravity waves at sloping boundaries leads to focusing or defocusing. In closed domains, focusing typically dominates and projects the wave energy onto ‘wave attractors’. For small-amplitude internal waves, the projection of energy onto higher wavenumbers by geometric focusing can be balanced by viscous dissipation at high wavenumbers. Contrary to what was previously suggested, viscous dissipation in interior shear layers may not be sufficient to explain the experiments on wave attractors in the classical quasi-two-dimensional trapezoidal laboratory set-ups. Applying standard boundary layer theory, we provide an elaborate description of the viscous dissipation in the interior shear layer, as well as at the rigid boundaries. Our analysis shows that even if the thin lateral Stokes boundary layers consist of no more than 1 % of the wall-to-wall distance, dissipation by lateral walls dominates at intermediate wave numbers. Our extended model for the spectrum of three-dimensional wave attractors in equilibrium closes the gap between observations and theory by Hazewinkel et al. (J. Fluid Mech., vol. 598, 2008, pp. 373–382).
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LITTLE, PATRICK. "THE IRISH ‘INDEPENDENTS’ AND VISCOUNT LISLE’S LIEUTENANCY OF IRELAND." Historical Journal 44, no. 4 (2001): 941–61. http://dx.doi.org/10.1017/s0018246x01001972.
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This article examines the influence of a distinct Irish Protestant faction on parliamentarian policy-making in the mid-1640s – the Irish Independents. These men were not merely clients of parliament’s lord lieutenant, Viscount Lisle, but formed a group with consistent personnel and policies, which can be traced back to the ‘Boyle group’ in the Irish council of the 1620s and 1630s. In the 1640s they came into an alliance with the English Independents, based on common hostility to the Presbyterian party, the Scots, and the supporters of Ormond and Inchiquin in Ireland. This coalition was, however, inherently unstable. Faced with equivocation at Westminster, where Ireland had always been low on the list of priorities, from December 1646 the Irish Independents were forced to take charge of parliament’s Irish policy, and many of the initiatives previously attributed to Lisle in 1646–7 can more properly be laid at their door. In conclusion, it is suggested that the Irish Independents represent a radical strain in Irish Protestantism, which supported Ireland’s closer integration into an ‘English Empire’, and which would see its fulfilment in the unionist agenda developed in the 1650s.
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Gómez-González, Manuel, and Juan C. del Álamo. "Flow of a viscous nematic fluid around a sphere." Journal of Fluid Mechanics 725 (May 14, 2013): 299–331. http://dx.doi.org/10.1017/jfm.2013.156.
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AbstractWe analyse the creeping flow generated by a spherical particle moving through a viscous fluid with nematic directional order, in which momentum diffusivity is anisotropic and which opposes resistance to bending. Specifically, we provide closed-form analytical expressions for the response function, i.e. the equivalent to Stokes’s drag formula for nematic fluids. Particular attention is given to the rotationally pseudo-isotropic condition defined by zero resistance to bending, and to the strain pseudo-isotropic condition defined by isotropic momentum diffusivity. We find the former to be consistent with the rheology of biopolymer networks and the latter to be closer to the rheology of nematic liquid crystals. These ‘pure’ anisotropic conditions are used to benchmark existing particle tracking microrheology methods that provide effective directional viscosities by applying Stokes’s drag law separately in different directions. We find that the effective viscosity approach is phenomenologically justified in rotationally isotropic fluids, although it leads to significant errors in the estimated viscosity coefficients. On the other hand, the mere concept of directional effective viscosities is found to be misleading in fluids that oppose an appreciable resistance to bending. Finally, we observe that anisotropic momentum diffusivity leads to asymmetric streamline patterns displaying enhanced (reduced) streamline deflection in the directions of lower (higher) diffusivity. The bending resistance of the fluid is found to modulate the asymmetry of streamline deflection. In some cases, the combined effects of both anisotropy mechanisms leads to streamline patterns that converge towards the sphere.
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Wang, C. Y. "Hydrodynamic Disk Braking." Journal of Applied Mechanics 52, no. 2 (1985): 263–66. http://dx.doi.org/10.1115/1.3169038.
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A viscous fluid separates a rotating disk and a parallel nonrotating disk. As the two disks are squeezed closer together, increased viscous torque is transmitted to the rotating disk. The Navier-Stokes equations are solved using a perturbation in the small squeeze number. Two cases of squeezing are studied: constant velocity approach and constant force approach.
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Das, S. K., and S. N. Das. "Modeling of Coupled Roll and Yaw Damping of a Floating Body in Waves." Mathematical Problems in Engineering 2007 (2007): 1–17. http://dx.doi.org/10.1155/2007/96373.
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A mathematical model is described to investigate the damping moment of weakly nonlinear roll and yaw motions of a floating body in time domain under the action of sinusoidal waves. The mathematical formulation for added mass moment of inertia and damping is presented by approximating time-dependent coefficients and forcing moments when small distortion holds. Using perturbation technique, we obtain orderwise equations wherein the closed-form solution is obtained for zeroth-order case, and for higher-order cases we resort to numerical integration using Runge-Kutta method with adaptive step-size algorithm. In order to analyze the model result, we perform numerical experiment for a vessel of 19190 tons under the beam wave of 1 m height and frequency 0.74 rad/s. Closer inspection in damping analysis reveals that viscous effect becomes significant for roll damping; whereas for yaw damping, contribution from added mass variation becomes significant.
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MYUNG, Y. S., B. H. CHO, YONGDUK KIM, and YOUNG-JAI PARK. "INFLATIONARY UNIVERSE IN SUPERSTRING THEORIES." Modern Physics Letters A 01, no. 03 (1986): 175–82. http://dx.doi.org/10.1142/s0217732386000257.
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We show that there are two non-equilibrium regions due to the inhomogeneous massive modes of the closed strings. The first region (T0<T<Tc) is more viscous and is dominated by the bulk viscosity. The second region (Te≤T≤T0) is less viscous and is described by the shear viscosity. In the less viscous region, considering the shear viscosity due to the transport of gravitational radiation, the large entropy may be produced owing to the inflation of 3-dimensional space and collapse of internal space.
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Bratsun, Dmitry, and Vladimir Vyatkin. "Closed-Form Non-Stationary Solutionsfor Thermo and Chemovibrational Viscous Flows." Fluids 4, no. 3 (2019): 175. http://dx.doi.org/10.3390/fluids4030175.
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A class of closed-form exact solutions for the Navier–Stokes equation written in the Boussinesq approximation is discussed. Solutions describe the motion of a non-homogeneous reacting fluid subjected to harmonic vibrations of low or finite frequency. Inhomogeneity of the medium arises due to the transversal density gradient which appears as a result of the exothermicity and chemical transformations due to a reaction. Ultimately, the physical mechanism of fluid motion is the unequal effect of a variable inertial field on laminar sublayers of different densities. We derive the solutions for several problems for thermo- and chemovibrational convections including the viscous flow of heat-generating fluid either in a plain layer or in a closed pipe and the viscous flow of fluid reacting according to a first-order chemical scheme under harmonic vibrations. Closed-form analytical expressions for fluid velocity, pressure, temperature, and reagent concentration are derived for each case. A general procedure to derive the exact solution is discussed.
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ROOS, P. C., and H. M. SCHUTTELAARS. "Horizontally viscous effects in a tidal basin: extending Taylor's problem." Journal of Fluid Mechanics 640 (October 27, 2009): 421–39. http://dx.doi.org/10.1017/s0022112009991327.
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The classical problem of Taylor (Proc. Lond. Math. Soc., vol. 20, 1921, pp. 148–181) of Kelvin wave reflection in a semi-enclosed rectangular basin of uniform depth is extended to account for horizontally viscous effects. To this end, we add horizontally viscous terms to the hydrodynamic model (linearized depth-averaged shallow-water equations on a rotating plane, including bottom friction) and introduce a no-slip condition at the closed boundaries.In a straight channel of infinite length, we obtain three types of wave solutions (normal modes). The first two wave types are viscous Kelvin and Poincaré modes. Compared to their inviscid counterparts, they display longitudinal boundary layers and a slight decrease in the characteristic length scales (wavelength or along-channel decay distance). For each viscous Poincaré mode, we additionally find a new mode with a nearly similar lateral structure. This third type, entirely due to viscous effects, represents evanescent waves with an along-channel decay distance bounded by the boundary-layer thickness.The solution to the viscous Taylor problem is then written as a superposition of these normal modes: an incoming Kelvin wave and a truncated sum of reflected modes. To satisfy no slip at the lateral boundary, we apply a Galerkin method. The solution displays boundary layers, the lateral one at the basin's closed end being created by the (new) modes of the third type. Amphidromic points, in the inviscid and frictionless case located on the centreline of the basin, are now found on a line making a small angle to the longitudinal direction. Using parameter values representative for the Southern Bight of the North Sea, we finally compare the modelled and observed tide propagation in this basin.
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Evatt, Geoffrey W. "Röthlisberger channels with finite ice depth and open channel flow." Annals of Glaciology 56, no. 70 (2015): 45–50. http://dx.doi.org/10.3189/2015aog70a992.
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AbstractThe theoretical basis of subglacial channel dynamics can be traced back to the work of Röthlisberger (1972) and Nye (1953). Röthlisberger (1972) considered the channels’ behaviour to be governed by a mix between water friction melting back the channel walls and the viscous closure of the surrounding ice; Nye (1953) derived a viscous closure rate for the ice. While their modelling is evidently well constructed, two aspects of their work have gone undeveloped. The first is the consideration of a finite glacier depth within the viscous closure law, instead of the assumption of an infinite glacier depth. The second is the allowance of a region of open channel flow, so that a channel’s water may transition from a region of closed channel flow to one where the water is exposed to the atmosphere. This paper helps close these two gaps, showing how Nye’s equation for the rate of ice closure can be modified, and how the point of transition between closed and open channel flow may be determined.
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Gruziel-Słomka, Magdalena, Paweł Kondratiuk, Piotr Szymczak, and Maria L. Ekiel-Jeżewska. "Stokesian dynamics of sedimenting elastic rings." Soft Matter 15, no. 36 (2019): 7262–74. http://dx.doi.org/10.1039/c9sm00598f.
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We study numerically the dynamics of elastic microfilaments which form closed loops and settle under gravity in a viscous fluid. We observe diversity of periodic and stationary sedimentation modes, dependent on flexibility and initial configuration.
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Zayed, El-Sayed M., and El-Sayed F. Elshehawey. "Eigenvalues of the time—dependent fluid flow problem I." International Journal of Mathematics and Mathematical Sciences 13, no. 1 (1990): 139–44. http://dx.doi.org/10.1155/s0161171290000187.
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The direct and inverse boundary value problems for the linear unsteady viscous fluid flow through a closed conduit of a circular annular cross-sectionΩwith arbitrary time-dependent pressure gradient under the third boundary conditions have been investigated.
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Salah El-Din, M. M. "Effect of viscous dissipation on laminar mixed convection in a horizontal channel." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 216, no. 3 (2002): 167–72. http://dx.doi.org/10.1243/095440802320225374.
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Laminar mixed convection in a horizontal channel is studied analytically in the fully developed region when the effect of viscous dissipation cannot be neglected. Two kinds of thermal boundary conditions are considered: uniform wall temperatures and uniform wall heat fluxes. Velocity and temperature profiles and the Nusselt numbers have been determined in a closed form. The results show that when viscous dissipation is taken into consideration, temperature profiles and Nusselt numbers are significantly affected by the Brinkman number while velocity profiles are independent of the Brinkman number.
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Anzuini, F., and A. Melatos. "Differential rotation in neutron stars with open and closed magnetic topologies." Monthly Notices of the Royal Astronomical Society 494, no. 3 (2020): 3095–109. http://dx.doi.org/10.1093/mnras/staa915.
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ABSTRACT Analytic arguments have been advanced that the degree of differential rotation in a neutron star depends on whether the topology of the internal magnetic field is open or closed. To test this assertion, the ideal-magnetohydrodynamics solver pluto is employed to investigate numerically the flow of an incompressible, viscous fluid threaded by a magnetic field with open and closed topologies in a conducting, differentially rotating, spherical shell. Rigid body corotation with the outer sphere is enforced on the Alfvén time-scale, along magnetic field lines that connect the northern and southern hemispheres of the outer sphere. Along other field lines, however, the behaviour is more complicated. For example, an initial point dipole field evolves to produce an approximately closed equatorial flux tube containing at least one predominantly toroidal and approximately closed field line surrounded by a bundle of predominantly toroidal but open field lines. Inside the equatorial flux tube, the field-line-averaged magnetic tension approaches zero, and the fluid rotates differentially, adjusting its angular velocity on the viscous time-scale to match the boundary conditions on the flux tube’s toroidal surface. Outside the equatorial flux tube, the differential rotation increases, as the magnetic tension averaged along open field lines decreases.
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Zhu, G., P. W. Bearman, and J. M. R. Graham. "Prediction of drag and lift of wings from velocity and vorticity fields." Aeronautical Journal 111, no. 1125 (2007): 699–704. http://dx.doi.org/10.1017/s0001924000004875.
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AbstractThe present paper continues the work of Zhuet al. The closed-form expressions for the evaluation of forces on a body in compressible, viscous and rotational flow derived in the previous paper have been extended to different forms. The expressions require only a knowledge of the velocity field (and its derivatives) in a finite and arbitrarily chosen region enclosing the body. The equations are implemented on three-dimensional inviscid flows over wings and wing/body combinations. Further implementation on three-dimensional viscous flows over wings has also been investigated.
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Wei, Yikun, Pingping Shen, Zhengdao Wang, Hong Liang, and Yuehong Qian. "Time Evolution Features of Entropy Generation Rate in Turbulent Rayleigh-Bénard Convection with Mixed Insulating and Conducting Boundary Conditions." Entropy 22, no. 6 (2020): 672. http://dx.doi.org/10.3390/e22060672.
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Time evolution features of kinetic and thermal entropy generation rates in turbulent Rayleigh-Bénard (RB) convection with mixed insulating and conducting boundary conditions at Ra = 109 are numerically investigated using the lattice Boltzmann method. The state of flow gradually develops from laminar flow to full turbulent thermal convection motion, and further evolves from full turbulent thermal convection to dissipation flow in the process of turbulent energy transfer. It was seen that the viscous, thermal, and total entropy generation rates gradually increase in wide range of t/τ < 32 with temporal evolution. However, the viscous, thermal, and total entropy generation rates evidently decrease at time t/τ = 64 compared to that of early time. The probability density function distributions, spatial-temporal features of the viscous, thermal, and total entropy generation rates in the closed system provide significant physical insight into the process of the energy injection, the kinetic energy, the kinetic energy transfer, the thermal energy transfer, the viscous dissipated flow and thermal dissipation.
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Debnath, Partha Sarathi. "Observational constraints of bulk viscous Friedmann–Robertson–Walker cosmology with hybrid expansion law." International Journal of Modern Physics A 35, no. 27 (2020): 2050173. http://dx.doi.org/10.1142/s0217751x20501730.
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In this work, we study bulk viscous Friedmann–Robertson–Walker cosmologies with hybrid expansion law. The bulk viscous theory of dissipative effects described by Eckart theory, truncated Israel–Stewart theory and full Israel–Stewart theory are implemented here. The hybrid expansion law model of scale factor is a general analytic type of evolution from which one can recover power-law and exponential expansion as a special cases. Hybrid expansion law model are applied to describe the present accelerating phase and early phases of evolution. We have determined the cosmological parameters such as Hubble parameter, deceleration parameter, jerk parameter, energy density, bulk viscous pressure and coefficient of bulk viscosity of the universe to construct physically acceptable cosmological model. We have considered both flat and closed space–time of Friedmann–Robertson–Walker cosmology to implement hybrid expansion law with dissipative effect. The variations of the coefficient of bulk viscosity with cosmic evolution are studied here in Eckart, truncated and full Israel–Stewart theory for flat and closed space–time to obtain physically acceptable hybrid expansion models driven by viscosity. We have also estimated observational constraints of the parameters of hybrid expansion law model by considering recent observational data set. We further reveal possible connections of our models with [Formula: see text] tension problem.
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Tawfik, A. "Thermodynamics in the viscous early universe." Canadian Journal of Physics 88, no. 11 (2010): 825–31. http://dx.doi.org/10.1139/p10-058.
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Assuming that the matter in the background geometry is a free gas and that no phase transitions were occurring in the early Universe, we discuss the thermodynamics of this closed system using classical approaches. We find that essential cosmological quantities, such as the Hubble parameter H, the scaling factor a, and the curvature parameter k, can be derived from this simple model, which on one hand fulfills and entirely obeys the laws of thermodynamics, and on the other hand, its results are compatible with the Friedmann–Robertson–Walker model and the Einstein field equations. Including a finite bulk viscosity coefficient leads to important changes in all these cosmological quantities. Accordingly, our picture about the evolution of the Universe and its astrophysical consequences seems to undergoing a radical revision. We find that k strongly depends on the thermodynamics of background matter. The time scale at which negative curvature might take place depends on the relation between the matter content and the total energy. Using quantum and statistical approaches, we introduce expressions for H and the bulk viscosity coefficient ξ.
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Abbas, Zaheer, Jafar Hasnain, and Muhammad Sajid. "Hydromagnetic Mixed Convective Two-Phase Flow of Couple Stress and Viscous Fluids in an Inclined Channel." Zeitschrift für Naturforschung A 69, no. 10-11 (2014): 553–61. http://dx.doi.org/10.5560/zna.2014-0048.
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AbstractAn analysis is carried out to study magnetohydrodynamic (MHD) flow and heat transfer of two immiscible fluids in an inclined channel. The channel is filled with couple stress fluid in one region and a viscous fluid in the other region. The viscous fluid is assumed to be electrically conducting. The governing equations are modelled using the fully developed flow conditions. A closed form solutions of velocity and the temperature profiles are obtained by using perturbation method. The physical interpretation of the emerging parameters of interest on the velocity and temperature distributions are shown through graphs and discussed in detail.
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Tripathi, J. P., U. P. Singh, and B. K. Singh. "Homotopy Analysis of Circular Plates Squeeze Film Bearings Lubricated with Couple Stress Fluids: Piezo-Viscous Model." Science & Technology Journal 8, no. 2 (2020): 95–102. http://dx.doi.org/10.22232/stj.2020.08.02.14.
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The piezo-viscous effect is crucial in fluid flows under high-pressure applications such as fluid film lubrication, microfluidics, and geophysics. We have investigated the combined influences of piezo-viscous dependence and non-Newtonian couple stresses on the performance of circular plate squeeze film bearings using Stokes Micro-Continuum theory of couple stress fluids together with the exponential variation of viscosity with pressure. A closed-form solution for film pressure has been obtained using the homotopy analysis method. The numerical results for pressure and load capacity with different values of the viscosity-pressure parameter have been calculated and compared with iso-viscous couple stress and Newtonian lubricants. An enhanced pressure and load capacity are observed in the analysis. The response time for the bearing (plate approach time) has also been calculated and a significant increase is observed.
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Wilczek, Michael, and Charles Meneveau. "Pressure Hessian and viscous contributions to velocity gradient statistics based on Gaussian random fields." Journal of Fluid Mechanics 756 (September 1, 2014): 191–225. http://dx.doi.org/10.1017/jfm.2014.367.
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AbstractUnderstanding the non-local pressure contributions and viscous effects on the small-scale statistics remains one of the central challenges in the study of homogeneous isotropic turbulence. Here we address this issue by studying the impact of the pressure Hessian as well as viscous diffusion on the statistics of the velocity gradient tensor in the framework of an exact statistical evolution equation. This evolution equation shares similarities with earlier phenomenological models for the Lagrangian velocity gradient tensor evolution, yet constitutes the starting point for a systematic study of the unclosed pressure Hessian and viscous diffusion terms. Based on the assumption of incompressible Gaussian velocity fields, closed expressions are obtained as the results of an evaluation of the characteristic functionals. The benefits and shortcomings of this Gaussian closure are discussed, and a generalization is proposed based on results from direct numerical simulations. This enhanced Gaussian closure yields, for example, insights on how the pressure Hessian prevents the finite-time singularity induced by the local self-amplification and how its interaction with viscous effects leads to the characteristic strain skewness phenomenon.
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Elbaz, S. B., and A. D. Gat. "Dynamics of viscous liquid within a closed elastic cylinder subject to external forces with application to soft robotics." Journal of Fluid Mechanics 758 (October 7, 2014): 221–37. http://dx.doi.org/10.1017/jfm.2014.527.
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AbstractViscous flows in contact with elastic structures apply both pressure and shear stress at the solid–liquid interface and thus create internal stress and deformation fields within the solid structure. We study the interaction between the deformation of elastic structures, subject to external forces, and an internal viscous liquid. We neglect inertia in the liquid and solid and focus on viscous flow through a thin-walled slender elastic cylindrical shell as a basic model of a soft robot. Our analysis yields an inhomogeneous linear diffusion equation governing the coupled viscous–elastic system. Solutions for the flow and deformation fields are obtained in closed analytical form. The functionality of the viscous–elastic diffusion process is explored within the context of soft-robotic applications, through analysis of selected solutions to the governing equation. Shell material compressibility is shown to have a unique effect in inducing different flow and deformation regimes. This research may prove valuable to applications such as micro-swimmers, micro-autonomous systems and soft robotics by allowing for the design and control of complex time-varying deformation fields.
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Ryham, Rolf J. "On the viscous flows of leak-out and spherical cap natation." Journal of Fluid Mechanics 836 (December 12, 2017): 502–31. http://dx.doi.org/10.1017/jfm.2017.807.
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This paper deals with the hydrodynamics of a viscous liquid passing through the hole in a deflating hollow sphere. I employ the method of complementary integrals and calculate in closed form the pressure and streamfunction for the axisymmetric, creeping motion coming from changes in radius. The resulting flow fields describe the motion of a deformable spherical cap in a viscous environment, where the deformations include changes in the size of the spherical cap, the size of the hole and translation of the body along the axis of symmetry. The calculations yield explicit expressions for the jumps in pressure and resistance coefficients for the combined deformations. The equation for the translation force shows that a freely suspended spherical cap is able to propel as an active swimmer. The expression for pressure contains the classic Sampson flow rate equation as a limiting case, but simulations show that the pressure must also account for the velocity of hole widening to correctly predict outflow rates in physiology. Movies based on the closed-form solutions visualize the flow fields and pressures as part of physical processes.
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Sher Akbar, Noreen, and Z. H. Khan. "Heat transfer analysis of bi-viscous ciliary motion fluid." International Journal of Biomathematics 08, no. 02 (2015): 1550026. http://dx.doi.org/10.1142/s1793524515500266.
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The impulsion system of cilia motion is deliberated by biviscosity fluid model. The problem of two-dimensional motion of biviscosity fluid privileged in a symmetric channel with ciliated walls is considered. The features of ciliary structures are resolute by the supremacy of viscous effects above inertial possessions by the long-wavelength and low Reynolds approximation. Closed-form solutions for the longitudinal pressure gradient, temperature and velocities are obtained. The pressure gradient and volume flow rate for different values of the biviscosity are also premeditated. The flow possessions for the biviscosity fluid resolute as a function of the cilia and metachronal wave velocity.
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Tang, You-Qi, Deng-Bo Zhang, and Jia-Ming Gao. "Vibration characteristic analysis and numerical confirmation of an axially moving plate with viscous damping." Journal of Vibration and Control 23, no. 5 (2016): 731–43. http://dx.doi.org/10.1177/1077546315586311.
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In this paper, the vibration characteristics of axially moving plates with viscous damping are analyzed. A partial differential linear equation of motion with four simply supported edges is presented. The effects of two different viscous damping models are highlighted, while both of them have been introduced in previous studies. The investigation into the two different viscous damping models is interesting in itself. It is noteworthy that which model is closer to the fact, for which there are no systematic techniques of investigation to deal with this problem. In order to give a reference for possible verification in experiment, the difference of the two different viscous damping models in theory was proposed. The complex frequencies and its corresponding complex modes are studied by the complex mode approach. As other parameters are fixed, the effect of some parameters, such as viscous damping coefficients, axial speeds, aspect ratios, stiffness ratios, and support stiffness parameters, on the frequencies and critical speeds are examined. The complex modes illustrated in the 3-demensional figures are neither symmetric nor anti-symmetric to the midpoint of the plate owing to the plate motion. The differential quadrature scheme is used to verify the modes for the first time. The numerical calculations confirm the analytical results.
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Huang, Sheng Nan, Xin Zheng Lu, and Lie Ping Ye. "Study on the Strengthening Effect of a Typical RC Frame in Wenchuan Earthquake with Attached Substructures." Applied Mechanics and Materials 353-356 (August 2013): 2057–64. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2057.
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This work is based on a typical RC frame that was closed to the epicenter and collapsed during the Wenchuan Earthquake. The seismic collapse resistance of the frame was strengthened by attached substructures, including conventional brace, buckling restrained brace (BRB) and viscous damper. Collapse fragility analysis based on incremental dynamic analysis is implemented for each strengthening scheme to compare their effects and to analyze the influence of critical parameters. The results show that the viscous damper performs better than the BRB, and the BRB performs better than the conventional brace. With the same strengthening parameters, the A-shaped bracing scheme is better than the X-shaped scheme.
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Fang, Tiegang, and Abdul Aziz. "Viscous Flow with Second-Order Slip Velocity over a Stretching Sheet." Zeitschrift für Naturforschung A 65, no. 12 (2010): 1087–92. http://dx.doi.org/10.1515/zna-2010-1212.
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In this paper, viscous flow with a second-order slip condition over a permeable stretching surface is solved analytically. The current work differs from the previous studies in the application of a new second-order slip velocity model. The closed form solution reported is an exact solution of the full governing Navier-Stokes equations. The effects of slip and mass transfer parameters are discussed.
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Young, D. L., and J. T. Chang. "Impulsive Motion of a Moving Circular Cylinder in a Viscous Flow by the Numerical Simulation." Journal of Mechanics 14, no. 3 (1998): 119–23. http://dx.doi.org/10.1017/s1727719100000149.
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ABSTRACTAn innovative computation procedure is developed to solve the external flow problems for viscous fluids. The method is able to handle the infinite domain so that it is convenient for the external flows. The code is based on the projection method of the Navier-Stokes equations. We use the three-step explicit finite element method to solve the momentum equation by extracting the boundary effects from the finite computation domain. The pressure Poisson equation for the external field is treated by the boundary element method. The arbitrary Lagrangian-Eulerian (ALE) scheme is employed to incorporate the present algorithm to deal with the moving boundary, such as the motion of an impulsively moving circular cylinder in a viscous fluid. The model demonstrates that drag force is well predicted for a circular cylinder moving in a still viscous fluid starting from rest, to a constant acceleration, and then maintaining at a uniform velocity. In the constant acceleration phase, the drag force is closed to the added mass effect from the ideal flow theory. On the other hand, the drag force is equal to viscous flow theory in the constant velocity phase.
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CATALDO, MAURICIO, SERGIO DEL CAMPO, PAUL MINNING, and FRANCISCO PEÑA. "A CAUSAL MODEL FOR A CLOSED UNIVERSE." International Journal of Modern Physics D 13, no. 05 (2004): 871–83. http://dx.doi.org/10.1142/s0218271804004943.
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We study a closed model of a universe filled with viscous fluid and quintessence matter components. The dynamical equations imply that the universe might look like an accelerated flat Friedmann–Robertson–Walker (FRW) universe at low redshift. We consider here dissipative processes which obey a causal thermodynamics. Here, we account for the entropy production via causal dissipative inflation.
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Hall,, Carsie A., and Calvin Mackie. "A Quasi-Steady Analytical Solution to Freezing Planar Couette Flow With Viscous Dissipation." Journal of Heat Transfer 123, no. 2 (2000): 407–11. http://dx.doi.org/10.1115/1.1351177.
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A quasi-steady analytical solution to freezing planar laminar Couette flow with viscous heating effects is presented. Closed-form expressions for the dimensionless freeze-front location, interface Nusselt number, and dimensionless power density (or dimensionless shear stress) are derived as a function of various dimensionless parameters. Several classical results are obtained in the appropriate asymptotic limits.
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Papageorgiou, Demetrios T. "Analytical description of the breakup of liquid jets." Journal of Fluid Mechanics 301 (October 25, 1995): 109–32. http://dx.doi.org/10.1017/s002211209500382x.
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A viscous or inviscid cylindrical jet with surface tension in a surrounding medium of negligible density tends to pinch owing to the mechanism of capillary instability. We construct similarity solutions which describe this phenomenon as a critical time is encountered, for three distinct cases: (i) inviscid jets governed by the Euler equations, (ii) highly viscous jets governed by the Stokes equations, and (iii) viscous jets governed by the Navier-Stokes equations. We look for singular solutions of the governing equations directly rather than by analysis of simplified models arising from slender-jet theories. For Stokes jets implicitly defined closed-form solutions are constructed which allow the scaling exponents to be fixed. Navier-Stokes pinching solutions follow rationally from the Stokes ones by bringing unsteady and nonlinear terms into the momentum equations to leading order. This balance fixes a set of universal scaling functions for the phenomenon. Finally we show how the pinching solutions can be used to provide an analytical description of the dynamics beyond breakup.
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CHALONS, C., and F. COQUEL. "THE RIEMANN PROBLEM FOR THE MULTI-PRESSURE EULER SYSTEM." Journal of Hyperbolic Differential Equations 02, no. 03 (2005): 745–82. http://dx.doi.org/10.1142/s0219891605000610.
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We prove the existence and uniqueness of the Riemann solutions to the Euler equations closed by N independent constitutive pressure laws. This model stands as a natural asymptotic system for the multi-pressure Navier–Stokes equations in the regime of infinite Reynolds number. Due to the inherent lack of conservation form in the viscous regularization, the limit system exhibits measure-valued source terms concentrated on shock discontinuities. These non-positive bounded measures, called kinetic relations, are known to provide a suitable tool to encode the small-scale sensitivity in the singular limit. Considering N independent polytropic pressure laws, we show that these kinetic relations can be derived by solving a simple algebraic problem which governs the endpoints of the underlying viscous shock profiles, for any given but prescribed ratio of viscosity coefficient in the viscous perturbation. The analysis based on traveling wave solutions allows us to introduce the asymptotic Euler system in the setting of piecewise Lipschitz continuous functions and to study the Riemann problem.
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Kang, Jae-Hoon. "Closed-Form Exact Solutions for Viscously Damped Free and Forced Vibrations of Longitudinal and Torsional Bars." International Journal of Structural Stability and Dynamics 17, no. 08 (2017): 1750093. http://dx.doi.org/10.1142/s0219455417500936.
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This paper studies the viscously damped free and forced vibrations of longitudinal and torsional bars. The method is exact and yields closed form solution for the vibration displacement in contrast with the well-known eigenfunction superposition (ES) method, which requires expression of the distributed forcing functions and displacement response functions as infinite series sums of free vibration eigenfunctions. The viscously damped natural frequency equation and the critical viscous damping equation are exactly derived for the bars. Then the viscously damped free vibration frequencies and corresponding damped mode shapes are calculated and plotted, aside from the undamped free vibration and corresponding mode shapes typically computed and used in vibration problems. The longitudinal or torsional amplitude versus forcing frequency curves showing the forced response to distributed loadings are plotted for various viscous damping parameters. It is found that the viscous damping affects the natural frequencies and the corresponding mode shapes of longitudinal and torsional bars, especially for the fundamental frequency.
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MEHMOOD, OBAID ULLAH, NORZIEHA MUSTAPHA, SHARIDAN SHAFIE, and CONSTANTIN FETECAU. "SIMULTANEOUS EFFECTS OF DISSIPATIVE HEATING AND PARTIAL SLIP ON PERISTALTIC TRANSPORT OF SISKO FLUID IN ASYMMETRIC CHANNEL." International Journal of Applied Mechanics 06, no. 01 (2014): 1450008. http://dx.doi.org/10.1142/s1758825114500082.
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This paper looks at the dissipative heat transfer on the peristaltic flow of a Sisko fluid in an asymmetric channel. Flow exhibits slip at the channel walls maintained at nonuniform temperatures. Long wavelength approximation is utilized and perturbation solutions are obtained about Sisko fluid parameter. Closed form solutions for the stream function, axial pressure gradient, axial velocity, temperature and the heat transfer coefficient are presented. Influences of various interesting parameters are presented in graphical and tabular forms. Pumping and trapping phenomena are discussed for increasing velocity slip parameter. A comparative study on temperature and heat transfer coefficient for viscous, shear thinning and shear thickening fluids has been presented. Comparisons for viscous fluid are found in good agreement.
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Mondal, Pranab Kumar, and Sanchayan Mukherjee. "Viscous dissipation effects on the limiting value of Nusselt numbers for a shear-driven flow through an asymmetrically heated annulus." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 12 (2012): 2941–49. http://dx.doi.org/10.1177/0954406212440671.
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In this study, an analytical investigation for analyzing the effects of viscous dissipation on the limiting Nusselt number for a hydro-dynamically fully developed laminar shear-driven flow through an asymmetrically heated annulus of two infinitely long concentric cylinders has been made, where the inner cylindrical rod is moving in an axial direction at a constant speed. On the basis of some common assumptions, an analytical framework has been devised to explore the effects of viscous dissipation on the heat transfer characteristics for the flow of Newtonian fluid, and, consequently, closed-form expressions for the limiting Nusselt numbers are evaluated. In the analysis, focus has been given on the viscous dissipative effect due to the shear produced by the movable inner cylindrical rod apart from the viscous dissipation due to internal fluid friction for the flow of a Newtonian fluid. The interactive effects of the Brinkman number and degree of asymmetry on the limiting Nusselt number are analytically investigated. It is observed from this study that the limiting Nusselt number becomes independent of Brinkman number when both the walls of the annulus are kept at an equal temperature. Moreover, the temperature profile in the conduction limit obtained with the consideration of viscous dissipation effect provides a boundary condition required for solving energy equation including the axial conduction in the fluid.
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Guria, M. "Unsteady Flow Through a Porous Medium Due to Non-coaxial Rotations of a Porous Disk and a Fluid at Infinity Subjected to a Periodic Suction." International Journal of Applied Mechanics and Engineering 23, no. 2 (2018): 401–11. http://dx.doi.org/10.2478/ijame-2018-0023.
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Abstract The unsteady flow of a viscous incompressible fluid due to non-coaxial rotations of a porous disk and a fluid at infinity subjected to a periodic suction through a porous medium has been studied. The velocity field, shear stresses are obtained in closed form. The variations of primary and secondary velocities for different values of non dimensional parameters are depicted in figures.
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Guria, M. "Unsteady MHD Flow Due to Non-Coaxial Rotations of a Porous Disk and a Fluid at Infinity Subjected to a Periodic Suction." International Journal of Applied Mechanics and Engineering 23, no. 3 (2018): 623–33. http://dx.doi.org/10.2478/ijame-2018-0034.
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Abstract The unsteady flow of a viscous incompressible electrically conducting fluid due to non-coaxial rotations of a porous disk subjected to a periodic suction and the fluid at infinity in the presence of applied transverse magnetic field has been studied. The fluid at infinity passes through a fixed point. The velocity field, shear stresses are obtained in a closed form.
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Ali, Nasir, Muhammad Sajid, and Tasawar Hayat. "Long Wavelength Flow Analysis in a Curved Channel." Zeitschrift für Naturforschung A 65, no. 3 (2010): 191–96. http://dx.doi.org/10.1515/zna-2010-0306.
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This study is concerned with the peristaltic flow of a viscous fluid in a curved channel. Mathematically the problem is governed by two partial differential equations. Closed form solutions of the stream function, axial velocity, and pressure gradient are developed under long wavelength and low Reynolds number assumptions. The influence of curvature is analyzed on various flow quantities of interest.
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Weislogel, Mark M. "Compound capillary rise." Journal of Fluid Mechanics 709 (August 23, 2012): 622–47. http://dx.doi.org/10.1017/jfm.2012.357.
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AbstractIrregular conduits, complex surfaces, and porous media often manifest more than one geometric wetting condition for spontaneous capillary flows. As a result, different regions of the flow exhibit different rates of flow, all the while sharing common dynamical capillary pressure boundary conditions. The classic problem of sudden capillary rise in tubes with interior corners is revisited from this perspective and solved numerically in the self-similar ${\ensuremath{\sim} }{t}^{1/ 2} $ visco-capillary limit à la Lucas–Washburn. Useful closed-form analytical solutions are obtained in asymptotic limits appropriate for many practical flows in conduits containing one or more interior corner. The critically wetted corners imbibe fluid away from the bulk capillary rise, shortening the viscous column length and slightly increasing the overall flow rate. The extent of the corner flow is small for many closed conduits, but becomes significant for flows along open channels and the method is extended to approximate hemiwicking flows across triangular grooved surfaces. It is shown that an accurate application of the method depends on an accurate a priori assessment of the competing viscous cross-section length scales, and the expedient Laplacian scaling method is applied herein toward this effect.
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Guntur, Harus Laksana, Wiwiek Hendrowati, and Tidy Budiarto. "Modeling and Analysis of Hybrid Shock Absorber for Military Vehicle Suspension." Applied Mechanics and Materials 493 (January 2014): 315–20. http://dx.doi.org/10.4028/www.scientific.net/amm.493.315.
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This paper deals with the design, modeling and analysis of a hybrid shock absorber for vehicle suspension. A specific design of frictional-electromagnetic-regenerative shock absorber is proposed. The hybrid shock absorber consists of the proposed frictional-electromagnetic-regenerative shock absorber assembled in parallel with a conventional-viscous shock absorber. The concept of hybrid shock absorber is proposed due to the following advantages: the regenerative shock absorber will recover some wasted vibration energy from the suspension into electrical energy to support the need for electrical energy of the vehicle, while the viscous shock absorber maintains the performance of suspension closed to its original suspension. The vehicle suspension system dynamic was mathematically modeled for three different types of suspension:1).Conventional suspension using viscous shock absorber; 2).Hybrid suspension using combination of 50% frictional-electromagnetic-regenerative shock absorberand50% viscous shock absorber; and 3).Full regenerative suspension using 100% frictional-electromagnetic-regenerative shock absorber. In this research, 6 wheels military vehicle (APC:Armour Personal Carrier) is chosen as the model due to the high possibility of applying regenerative suspension to the military/off road vehicle. Based on the mathematical models, performances of the vehicle suspension and the regenerated power from regenerative shock absorber (RSA) were simulated. The results were compared between the three types of suspension and discussed.
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Guntur, Harus Laksana, and Wiwiek Hendrowati. "A Comparative Study of the Damping Force and Energy Absorbtion Capacity of Regenerative and Conventional-Viscous Shock Absorber of Vehicle Suspension." Applied Mechanics and Materials 758 (April 2015): 45–50. http://dx.doi.org/10.4028/www.scientific.net/amm.758.45.
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This paper presents a comparative study of the damping force and energy absorbtion capacity of a typical conventional-viscous and a regenerative shock absorber for vehicle suspension. Regenerative shock absorber (RSA) is a shock absorber which can regenerate the dissipated vibration energy from vehicle suspension into electricity. In this research, a prototype of regenerative shock absorber was developed, its damping force and energy absorbtion capacity were tested, and the results were analized and compared with those of a typical conventional-viscous shock absorber. The regenerative and viscous shock absorber were compressed and extended in various excitation frequency using damping force testing equipment to obtain force-velocity and the force-displacement curves. The force-velocity and force-displacement curves indicate the damping force and energy absorbtion capacity of the shock absorber. The results show that the damping force of the typical-viscous shock absorber closed to linear at all exciation frequencies. For regenerative shock absorber, nonlinearity and large hysteresis area of the damping force occur at all excitation frequencies. Further, the energy absorbtion capacity of the typical-viscous shock absorber shows an elliptical area with the compression part bigger than the extension one, while those of the regenerative shock absorber shows an asymmetric square area, which indicates a smaller energy absorbtion capacity. These phenomena indicate the significant effect of implementing dry friction damper and elctrical damper to the characteristics of regenerative shock absorber.
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Padhy, S. K. "Lubrication Analysis of a Rolling Piston Rotary Compressor: Part 1: Mathematical Modelling." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 208, no. 2 (1994): 83–94. http://dx.doi.org/10.1243/pime_proc_1994_208_355_02.
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This paper describes a mathematical model for the lubrication system of a single-vane rolling piston type rotary compressor. The lubricant flow in the compressor is modelled as a flow in a pipe network. Various flow resistances, pressure differentials and viscous pump effects are determined. Closed network equations are formulated. The equations are solved simultaneously, and the lubricant flowrates at various clearances of the compressor are calculated.
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Katayama, Shingo, and Masahiro Sekine. "Fabrication of superconducting YBa2Cu3O7−x fibers by the sol-gel method using metal alkoxides." Journal of Materials Research 6, no. 8 (1991): 1629–33. http://dx.doi.org/10.1557/jmr.1991.1629.
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Superconducting YBa2Cu3O7−x fibers were fabricated by the sol-gel method using modified metal alkoxides. To prepare a heterometallic alkoxide as a precursor of a homogeneous and viscous sol, Y and Cu alkoxides were modified with ethyl acetoacetate (EAA) and ethylenediamine (en), respectively. Their structures were determined by FT-IR and EXAFS. The heterometallic alkoxide was synthesized by partial hydrolysis of the modified alkoxides and was further hydrolyzed and concentrated to obtain a viscous sol. This sol had good spinability and was spun into gel fibers by a spinning apparatus. The gel fibers had a high oxide content of 61 wt.%. The fiber, fired at 950 °C for 10 h in O2, had only closed pores and a dense structure. Tc (onset) of this fiber was 94 K.
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Ramakrishnan, T. S., P. Wu, H. Zhang, and D. T. Wasan. "Dynamics in closed and open capillaries." Journal of Fluid Mechanics 872 (June 7, 2019): 5–38. http://dx.doi.org/10.1017/jfm.2019.328.
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Capillary rise of a liquid displacing gas is analysed for both open and closed capillaries. We include menisci mass and hysteresis, and show that oscillations due to inertia are muted by friction at the advancing meniscus. From single-phase numerical computations in a no-slip/slip capillary, we quantify losses due to entry, flow development, meniscus slip, exit and acceleration of fluid within the reservoir. For closed capillaries, determining viscous drag due to gas requires inclusion of compressibility, and solving a moving boundary problem. This solution is derived through perturbation expansion with respect to two different small parameters for obtaining pressure above the liquid meniscus. Our rise predictions spanning a large range of experimental conditions and fluids for both open and closed capillaries match the data. The experimental data confirm the adequacy of the theoretically constructed dimensionless groups for predicting oscillatory behaviour.
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Jha, Basant K., and Taiwo S. Yusuf. "Entropy generation in an inclined porous channel with suction/injection." Nonlinear Engineering 9, no. 1 (2019): 94–104. http://dx.doi.org/10.1515/nleng-2018-0116.
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AbstractThe present work is concerned with an analytical study of entropy generation in viscous, incompressible fluid in an inclined channel with porous walls. The solution of the governing equations were obtained in closed form. The expression for the irreversibility ratio was also obtained and the results were presented graphically and extensively discussed for different values of the dimensionless parameters. The result indicates that wall inclination enhance entropy generation.
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Fan, Xue Liu, Xiang Chen, and Yan Xiang Li. "The Structure and Acoustic Properties of Aluminum Foams by Gas Injection Method." Advanced Materials Research 146-147 (October 2010): 1049–55. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1049.
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The acoustic properties of aluminum foams by gas injection method were studied experimentally. The micro and macro structure of aluminum foam with closed cells were observed by optical microscope (OM) and scanning electron microscope (SEM). The special structure of the closed-pores of the aluminum foams have leaded to good performance of the sound absorption based on three mechanisms: Helmholtz resonance, cell wall vibration and viscous and thermal effects. The effect of cell sizes, thickness of aluminum foams has been investigated and the cavity set at the back of the foam samples on the sound absorption efficiency of the foams has been measured. Analytical models of membrane vibrations were used to explain the sound absorption capacity of the foams.
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Lee, K. S. "Effects of Sipes on the Viscous Hydroplaning of Pneumatic Tires." Tire Science and Technology 26, no. 1 (1998): 23–35. http://dx.doi.org/10.2346/1.2135955.
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Abstract Using a finite element calculation, this study seeks to evaluate the effects of sipes on the transient behavior of viscous hydroplaning: fluid pressure distribution, fluid film thickness, and descending velocity as a function of time. From calculations on block-type tread elements with open or closed sipes, sipes in the low velocity region in the thin fluid film have been shown to be very effective in controlling the occurrence of viscous hydroplaning. Application of the transient analysis procedure to rib-type tread elements showed that highly zigzagged tread elements with a sipe at the line of symmetry are more effective for traction on wet pavement. Results from the study provide qualitative and quantitative guidelines to tire designers in the search for the optimum pattern of individual tread elements on the basis of thin film wet traction.
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Shi, Zhi Guang, and Wei Huo. "Robust Tracking for BLDCM System Based on Unknown Differentiable Deadzone Nonlinearity." Applied Mechanics and Materials 313-314 (March 2013): 530–34. http://dx.doi.org/10.4028/www.scientific.net/amm.313-314.530.
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In this paper, trajectory tracking control of the brushless DC motor system (BLDCMS) with parameter unknown deadzone nonlinearity and viscous friction is investigated. Firstly, a global differential homeomorphism based on the recently established differentiable deadzone model is developed to linearize BLDCMS. Then, a model reference robust controller is presented to suppress the uncertainties. Finally, uniformly ultimate boundedness of the closed-loop system is proved and simulation results show validity of the proposed controller.
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CAMASSA, ROBERTO, RICHARD M. McLAUGHLIN, and LONGHUA ZHAO. "Lagrangian blocking in highly viscous shear flows past a sphere." Journal of Fluid Mechanics 669 (February 16, 2011): 120–66. http://dx.doi.org/10.1017/s0022112010004933.
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An analytical and computational study of Lagrangian trajectories for linear shear flow past a sphere or spheroid at low Reynolds numbers is presented. Using the exact solutions available for the fluid flow in this geometry, we discover and analyse blocking phenomena, local bifurcation structures and their influence on dynamical effects arising in the fluid particle paths. In particular, building on the work by Chwang & Wu, who established an intriguing blocking phenomenon in two-dimensional flows, whereby a cylinder placed in a linear shear prevents an unbounded region of upstream fluid from passing the body, we show that a similar blocking exists in three-dimensional flows. For the special case when the sphere is centred on the zero-velocity plane of the background shear, the separatrix streamline surfaces which bound the blocked region are computable in closed form by quadrature. This allows estimation of the cross-sectional area of the blocked flow showing how the area transitions from finite to infinite values, depending on the cross-section location relative to the body. When the sphere is off-centre, the quadrature appears to be unavailable due to the broken up-down mirror symmetry. In this case, computations provide evidence for the persistence of the blocking region. Furthermore, we document a complex bifurcation structure in the particle trajectories as the sphere centre is moved from the zero-velocity plane of the background flow. We compute analytically the emergence of different fixed points in the flow and characterize the global streamline topology associated with these fixed points, which includes the emergence of a three-dimensional bounded eddy. Similar results for the case of spheroids are considered in Appendix B. Additionally, the broken symmetry offered by a tilted spheroid geometry induces new three-dimensional effects on streamline deflection, which can be viewed as effective positive or negative suction in the horizontal direction orthogonal to the background flow, depending on the tilt orientation. We conclude this study with results on the case of a sphere embedded at a generic position in a rotating background flow, with its own prescribed rotation including fixed and freely rotating. Exact closed-form solutions for fluid particle trajectories are derived.
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Chliamovitch, Gregor, and Yann Thorimbert. "Turbulence through the Spyglass of Bilocal Kinetics." Entropy 20, no. 7 (2018): 539. http://dx.doi.org/10.3390/e20070539.
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In two recent papers we introduced a generalization of Boltzmann’s assumption of molecular chaos based on a criterion of maximum entropy, which allowed setting up a bilocal version of Boltzmann’s kinetic equation. The present paper aims to investigate how the essentially non-local character of turbulent flows can be addressed through this bilocal kinetic description, instead of the more standard approach through the local Euler/Navier–Stokes equation. Balance equations appropriate to this kinetic scheme are derived and closed so as to provide bilocal hydrodynamical equations at the non-viscous order. These equations essentially consist of two copies of the usual local equations, but coupled through a bilocal pressure tensor. Interestingly, our formalism automatically produces a closed transport equation for this coupling term.