Journal articles: 'Slip boundary condition'

1

Raghunandana, John, and Kanthraj. "Stability of Journal Bearings Considering Slip Condition: A Non Linear Transient Analysis." Asian Journal of Engineering and Applied Technology 1, no. 2 (2012): 26–30. http://dx.doi.org/10.51983/ajeat-2012.1.2.2493.

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The no-slip boundary condition is the foundation of traditional lubrication theory. For most practical applications the no-slip boundary condition is a good model for predicting fluid behavior. However, recent experimental research has found that for special engineered surfaces the no-slip boundary condition is not applicable. In the present study the non linear transient analysis of an engineered slip/no-slip surface on journal bearing performance is examined. Numerical Analysis is carried out by solving the modified Reynolds equation satisfying the boundary conditions using successive over relaxation scheme in a finite difference grid which gives the steady state pressure. An attempt is made to evaluate the mass parameter (a measure of stability) besides finding out the steady-state characteristics of the finite journal bearing.

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2

Borzenko, Evgeny, and Olga Dyakova. "Numerical Simulation of Newtonian Fluid Flow in a T-Channel with no Slip/Slip Boundary Conditions on a Solid Wall." Key Engineering Materials 743 (July 2017): 480–85. http://dx.doi.org/10.4028/www.scientific.net/kem.743.480.

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The planar flow of a Newtonian incompressible fluid in a T-shaped channel is investigated. Three fluid interaction models with solid walls are considered: no slip boundary condition, Navier slip boundary condition and slip boundary condition with slip yield stress. The fluid flow is provided by uniform pressure profiles at the boundary sections of the channel. The problem is numerically solved using a finite difference method based on the SIMPLE procedure. Characteristic flow regimes have been found for the described models of liquid interaction with solid walls. The estimation of the influence of the Reynolds number, pressure applied to the boundary sections and the parameters of these models on the flow pattern was performed. The criterial dependences describing main characteristics of the flow under conditions of the present work have been demonstrated.

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3

Abbatiello, Anna, Miroslav Bulíček, and Erika Maringová. "On the dynamic slip boundary condition for Navier–Stokes-like problems." Mathematical Models and Methods in Applied Sciences 31, no. 11 (2021): 2165–212. http://dx.doi.org/10.1142/s0218202521500470.

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The choice of the boundary conditions in mechanical problems has to reflect the interaction of the considered material with the surface. Still the assumption of the no-slip condition is preferred in order to avoid boundary terms in the analysis and slipping effects are usually overlooked. Besides the “static slip models”, there are phenomena that are not accurately described by them, e.g. at the moment when the slip changes rapidly, the wall shear stress and the slip can exhibit a sudden overshoot and subsequent relaxation. When these effects become significant, the so-called dynamic slip phenomenon occurs. We develop a mathematical analysis of Navier–Stokes-like problems with a dynamic slip boundary condition, which requires a proper generalization of the Gelfand triplet and the corresponding function space setting.

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4

Hasegawa, Masato, Takumi Shimizu, Yoshio Matsui, and Hisanori Ueno. "Analysis of drag reduction with slip/no-slip boundary condition." Proceedings of Conference of Hokuriku-Shinetsu Branch 2004.41 (2004): 79–80. http://dx.doi.org/10.1299/jsmehs.2004.41.79.

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Duan, Jin Xi, and Z. Shen. "Elastic Seismic Response of Steel-Concrete Composite Frames with Partial Interaction." Applied Mechanics and Materials 268-270 (December 2012): 729–32. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.729.

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The finite element formulations of steel-concrete composite (SCC) beams considering interlayer slip with end shear restraint is established. Elastic seismic response of SCC frame structures under different shear connection stiffness and slip boundary conditions are examined. The influences of the shear connection stiffness and the slip boundary condition on elastic seismic response are analyzed. With the shear connection stiffness increasing, the free vibration frequencies increase and the seismic responses decrease. The natural vibration properties of SCC frame structures and seismic responses are also significantly affected by the slip boundary condition, and it should be properly imposed on all composite beams in seismic response analysis.

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6

LE ROUX, C. "STEADY STOKES FLOWS WITH THRESHOLD SLIP BOUNDARY CONDITIONS." Mathematical Models and Methods in Applied Sciences 15, no. 08 (2005): 1141–68. http://dx.doi.org/10.1142/s0218202505000686.

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We prove the existence, uniqueness and continuous dependence on the data of weak solutions to boundary-value problems that model steady flows of incompressible Newtonian fluids with wall slip in bounded domains. The flows satisfy the Stokes equations and a nonlinear slip boundary condition: for slip to occur, the magnitude of the tangential traction must exceed a prescribed threshold, which is independent of the normal stress, and where slip occurs the tangential traction is equal to a prescribed, possibly nonlinear, function of the slip velocity. In addition, a Dirichlet condition is imposed on a component of the boundary if the domain is rotationally symmetric. The method of proof is based on a variational inequality formulation of the problem and fixed point arguments which utilize wellposedness results for the Stokes problem with a slip condition of the "friction type".

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7

MATTHEWS, MICCAL T., and KAREN M. HASTIE. "AN ANALYTICAL AND NUMERICAL STUDY OF UNSTEADY CHANNEL FLOW WITH SLIP." ANZIAM Journal 53, no. 4 (2012): 321–36. http://dx.doi.org/10.1017/s1446181112000272.

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AbstractA theoretical investigation of the unsteady flow of a Newtonian fluid through a channel is presented using an alternative boundary condition to the standard no-slip condition, namely the Navier boundary condition, independently proposed over a hundred years ago by both Navier and Maxwell. This boundary condition contains an extra parameter called the slip length, and the most general case of a constant but different slip length on each channel wall is studied. An analytical solution for the velocity distribution through the channel is obtained via a Fourier series, and is used as a benchmark for numerical simulations performed utilizing a finite element analysis modified with a penalty method to implement the slip boundary condition. Comparison between the analytical and numerical solution shows excellent agreement for all combinations of slip lengths considered.

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Xia, Jun, Z. Shen, and Bin Chen. "Dynamic Analysis of Steel-Concrete Composite Frames with Partial Interaction." Advanced Materials Research 594-597 (November 2012): 904–7. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.904.

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The finite element formulations of steel-concrete composite (SCC) beams considering interlayer slip with end shear restraint were established. Free vibrations of SCC beams and frame structures under different slip boundary conditions were examined. The influences of the shear connection stiffness and the slip boundary condition on dynamic characteristics were analyzed. It is shown that the low order 8-DOF element may exhibit slip locking phenomenon in free vibration analysis for very stiff connection. The free vibration frequencies of composite beams and frame structures increase with the shear connection stiffness increasing. Besides, it is found that the natural vibration properties of SCC frame structures are significantly affected by the slip boundary condition, and it should be suitably imposed on all composite beams in dynamic analysis.

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9

Durbin, P. A. "Considerations on the moving contact-line singularity, with application to frictional drag on a slender drop." Journal of Fluid Mechanics 197 (December 1988): 157–69. http://dx.doi.org/10.1017/s0022112088003210.

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It has previously been shown that the no-slip boundary condition leads to a singularity at a moving contact line and that this forces one to admit some form of slip. Present considerations on the energetics of slip due to shear stress lead to a yield stress boundary condition. A model for the distortion of the liquid state near solid boundaries gives a physical basis for this boundary condition. The yield stress condition is illustrated by an analysis of a slender drop rolling down an incline. That analysis provides a formula for the frictional drag resisting the drop movement. With the present boundary condition the length of the slip region becomes a property of the fluid flow.

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10

Gu, Yandong, Jinwu Cheng, Hao Sun, Ao Liang, and Li Cheng. "A Three-Dimensional Slip Velocity Model for Water-Lubricated Hydrodynamic Journal Bearings." Journal of Marine Science and Engineering 10, no. 7 (2022): 927. http://dx.doi.org/10.3390/jmse10070927.

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Hydrodynamic journal bearings, coated with polytetrafluoroethylene (PTFE) and lubricated by water, have been widely used in ships and large-scale pumps, and the function is to maintain the stability of rotor system. However, slip velocity exists on the PTFE-coated surface, whose effect is still an open question. This study aims to investigate the static characteristics of water-lubricated hydrodynamic journal bearings under three-dimensional slip velocity boundary conditions. Firstly, under the non-slip boundary condition, the CFD (computational fluid dynamics) method with ANSYS Fluent is verified based on the Reynolds lubrication equation and the open literature. Then, a three-dimensional slip velocity equation that is based on the Navier slip velocity boundary condition is proposed and embedded into Fluent. Finally, the effects of slip length on the static characteristics are analyzed. Under the same eccentricity ratio, with the increase in slip length, the load capacity decreases due to the decrease of the pressure circumferential gradient, and the friction power decreases. Under the same eccentricity ratio and the same slip length, with the increase in the attitude angle, the load capacity and friction power increase. However, under the non-slip boundary condition, the effects of attitude angle on the load capacity and friction power are insignificant. This paper could provide a reference for studying slip velocity in the hydrodynamic journal bearing.

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11

Jamil, Muhammad, and Israr Ahmed. "Twice Order Slip on the Flows of Fractionalized MHD Viscoelastic Fluid." European Journal of Pure and Applied Mathematics 12, no. 3 (2019): 1018–51. http://dx.doi.org/10.29020/nybg.ejpam.v12i3.3455.

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The objective of this article is to investigate the effect of twice order slip on the MHD flow of fractionalized Maxwell fluid through a permeable medium produced by oscillatory movement of an infinite bottom plate. The governing equations are developed by fractional calculus approach. The exact analytical results for velocity field and related shear stress are calculated using Laplace transforms and presented in terms of generalized M-function satisfying all imposed initial and boundary conditions. The flow results for fractionalized Maxwell, traditional Maxwell and Newtonian fluid with and without slips, in the presence and absence of magnetic and porous effects are derived as the limiting cases. The impact of fractional parameter, slip coefficients, magnetic force and porosity parameter over the velocity field and shear stress are discussed and analyzed through graphical illustrations. The outcomes demonstrate that the speed comparing to streams with slip condition is lower than that for stream with non-slip conditions, and the speed with second-slip condition is lower than that with first-order slip condition.

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12

Xu, Mingtian. "Slip boundary condition of heat flux in Knudsen layers." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, no. 2161 (2014): 20130578. http://dx.doi.org/10.1098/rspa.2013.0578.

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In a Knudsen layer with thickness comparable to the mean free path, collisions between heat carriers and solid walls play an important role in nanoscale heat transports. An interesting question is that whether these collisions also induce the slip of heat flow similar to the velocity slip condition of the rarefied gases on solid walls. In this work based on the discrete Boltzmann transport equation, the slip boundary condition of heat flux on solid walls in the Knudsen layer is established. This result is exemplified by the slip boundary condition of heat flux in nanowires, which has been proposed in a phenomenological way.

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13

SAJID, M., N. ALI, Z. ABBAS, and T. JAVED. "STRETCHING FLOWS WITH GENERAL SLIP BOUNDARY CONDITION." International Journal of Modern Physics B 24, no. 30 (2010): 5939–47. http://dx.doi.org/10.1142/s0217979210055512.

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General slip boundary condition is used to solve the viscous incompressible flows induced by a stretching sheet. These flow problems corresponds to the planar and axisymmetric stretching. A similarity solution is developed by shooting method using Runge–Kutta algorithm. The results are graphically displayed and discussed under the influence of slip parameter and critical shear rate. The comparison of stretching flow problem subject to Navier's boundary condition in the planar case is made with the available numerical results in the literature.

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14

Wang, Ruifei, Jin Chai, Bobo Luo, et al. "A review on slip boundary conditions at the nanoscale: recent development and applications." Beilstein Journal of Nanotechnology 12 (November 17, 2021): 1237–51. http://dx.doi.org/10.3762/bjnano.12.91.

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The slip boundary condition for nanoflows is a key component of nanohydrodynamics theory, and can play a significant role in the design and fabrication of nanofluidic devices. In this review, focused on the slip boundary conditions for nanoconfined liquid flows, we firstly summarize some basic concepts about slip length including its definition and categories. Then, the effects of different interfacial properties on slip length are analyzed. On strong hydrophilic surfaces, a negative slip length exists and varies with the external driving force. In addition, depending on whether there is a true slip length, the amplitude of surface roughness has different influences on the effective slip length. The composition of surface textures, including isotropic and anisotropic textures, can also affect the effective slip length. Finally, potential applications of nanofluidics with a tunable slip length are discussed and future directions related to slip boundary conditions for nanoscale flow systems are addressed.

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15

Abdul-Jabbar, Jinan Raad. "The Effect of Slip Boundary Conditions on The Newtonian Die-Swell Flow." BASRA JOURNAL OF SCIENCE 41, no. 1 (2023): 1–12. http://dx.doi.org/10.29072/basjs.20230101.

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The effect of the slip boundary condition on the Newtonian die-swell free surface issue is the main objective of this study. The major aspect of this article is the determination of the free surface position using the free surface location methodology under the slip boundary condition. A Taylor Galerkin/pressure-correction (TG/PC) finite element method is used to solve this issue numerically. Furthermore, the system of equations that governs such a problem includes a time-dependent momentum equation and a continuity equation for mass conservation. These equations are shown here in an axisymmetric frame with Newtonian flow. The free-surface location is calculated using the Phan-Thien (dh/dt) approach in conjunction with slip boundary impact. This work focuses on the effect of slip boundary condition on swelling ratio for Newtonian representation. The current findings reveal that the slip boundary condition has a considerable impact on the swelling ratio of the fluid, causing a decrease in the fluid swell. Furthermore, the behaviors of solution components are presented.

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16

Li, Hongyuan, Yufan Cao, Xiangyu Wang, et al. "Accurate PIV measurement on slip boundary using single-pixel algorithm." Measurement Science and Technology 33, no. 5 (2022): 055302. http://dx.doi.org/10.1088/1361-6501/ac42b1.

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Abstract To accurately measure the near-wall flow by particle image velocimetry (PIV) is a big challenge, especially for the slip boundary condition. Apart from high-precision measurements, an appropriate PIV algorithm is important to resolve the near-wall velocity profile. In our study, the single-pixel algorithm is employed to calculate the near-wall flow, which is demonstrated to be capable of accurately resolving the flow velocity near the slip boundary condition. Based on synthetic particle images, the advantages of the single-pixel algorithm are manifested in comparison with the conventional window-correlation algorithm. In particular, the single-pixel algorithm has higher spatial resolution and accuracy, and lower systematic error and random error for the case of the slip boundary condition. Furthermore, for experimental verification, micro-PIV measurements are conducted over a liquid–gas interface, and the single-pixel algorithm is successfully applied to the calculation of near-wall velocity under the slip boundary condition, especially negative slip velocity. The current work demonstrates the advantages of the single-pixel algorithm in analyzing complex flows under the slip boundary condition, such as in drag reduction, wall skin-friction evaluation, and near-wall vortex structure measurement.

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17

SBRAGAGLIA, M., and A. PROSPERETTI. "Effective velocity boundary condition at a mixed slip surface." Journal of Fluid Mechanics 578 (April 26, 2007): 435–51. http://dx.doi.org/10.1017/s0022112007005149.

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This paper studies the nature of the effective velocity boundary condition for liquid flow over a plane boundary on which small free-slip islands are randomly distributed. It is found that an effective Navier partial-slip condition for the velocity emerges from a statistical analysis valid for arbitrary fractional area coverage β. As an example, the general theory is applied to the low-β limit and this result is extended heuristically to finite β with a resulting slip length proportional toaβ/(1 − β), whereais a characteristic size of the islands. A specification of the nature of the free-slip islands is not required in the analysis. They could be nano-bubbles, as suggested by recent experiments, or hydrophobic surface patches. The results are also relevant for ultra-hydrophobic surfaces exploiting the so-called ‘lotus effect’.

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18

Cho, Dae-Geun, Jung-Gil Na, Jae-Boong Choi, Young-Jin Kim, and Taesung Kim. "Effect of Slip Boundary Condition on the Design of Nanoparticle Focusing Lenses." Journal of Nanoscience and Nanotechnology 8, no. 7 (2008): 3741–48. http://dx.doi.org/10.1166/jnn.2008.18339.

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The importance of nanoparticles as a building block for novel application has been emphasized in various fields. Especially, nanoparticle beam has been widely used to measure particle size distribution, synthesize materials, and generate micro-patterns, as it can enhance the measurement resolution and transport efficiency. The aerodynamic lens system has been developed to focus particles in a certain size range. The manufacturing of nanoparticles in gas phase is typically performed at the low pressure conditions and the design and simulation of lens at low pressure have been steadily reported. The computational fluid dynamics (CFD) has been utilized to analyze the flow field and obtain particle trajectories. However, previous work has used no-slip boundary condition at low pressure. This paper describes the lens design and simulation with slip boundary condition at low pressure (∼1 Torr). The design of lens is discussed on the basis of the Wang et al.'s guidelines and the commercial code FLUENT is used for simulation. The results of this study show that the difference of particle beam radius between no-slip and slip boundary conditions is 0.03∼0.9 mm for particle size ranging from 3 to 200 nm with Brownian diffusion and that the transport efficiency is slightly higher with slip boundary condition.

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19

WILLEMSEN, S. M., H. C. J. HOEFSLOOT, and P. D. IEDEMA. "NO-SLIP BOUNDARY CONDITION IN DISSIPATIVE PARTICLE DYNAMICS." International Journal of Modern Physics C 11, no. 05 (2000): 881–90. http://dx.doi.org/10.1142/s0129183100000778.

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Dissipative Particle Dynamics (DPD) has, with only a few exceptions, been used to study hydrodynamic behavior of complex fluids without confinement. Previous studies used a periodic boundary condition, and only bulk behavior can be studied effectively. However, if solid walls play an important role in the problem to be studied, a no-slip boundary condition in DPD is required. Until now the methods used to impose a solid wall consisted of a frozen layer of particles. If the wall density is equal to the density of the simulated domain, slip phenomena are observed. To suppress this slip, the density of the wall has to be increased. We introduce a new method, which intrinsically imposes the no-slip boundary condition without the need to artificially increase the density in the wall. The method is tested in both a steady-state and an instationary calculation. If repulsion is applied in frozen particle methods, density distortions are observed. We propose a method to avoid these distortions. Finally, this method is tested against conventional computational fluid dynamics (CFD) calculations for the flow in a lid-driven cavity. Excellent agreement between the two methods is found.

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20

FUJII, Takehiro, Takeshi OMORI, and Takeo KAJISHIMA. "The immersed boundary projection method for the slip boundary condition." Proceedings of the Fluids engineering conference 2020 (2020): OS06–13. http://dx.doi.org/10.1299/jsmefed.2020.os06-13.

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21

Bae, Hyunji Jane, Adrián Lozano-Durán, Sanjeeb T. Bose, and Parviz Moin. "Dynamic slip wall model for large-eddy simulation." Journal of Fluid Mechanics 859 (November 16, 2018): 400–432. http://dx.doi.org/10.1017/jfm.2018.838.

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Wall modelling in large-eddy simulation (LES) is necessary to overcome the prohibitive near-wall resolution requirements in high-Reynolds-number turbulent flows. Most existing wall models rely on assumptions about the state of the boundary layer and require a priori prescription of tunable coefficients. They also impose the predicted wall stress by replacing the no-slip boundary condition at the wall with a Neumann boundary condition in the wall-parallel directions while maintaining the no-transpiration condition in the wall-normal direction. In the present study, we first motivate and analyse the Robin (slip) boundary condition with transpiration (non-zero wall-normal velocity) in the context of wall-modelled LES. The effect of the slip boundary condition on the one-point statistics of the flow is investigated in LES of turbulent channel flow and a flat-plate turbulent boundary layer. It is shown that the slip condition provides a framework to compensate for the deficit or excess of mean momentum at the wall. Moreover, the resulting non-zero stress at the wall alleviates the well-known problem of the wall-stress under-estimation by current subgrid-scale (SGS) models (Jiménez & Moser, AIAA J., vol. 38 (4), 2000, pp. 605–612). Second, we discuss the requirements for the slip condition to be used in conjunction with wall models and derive the equation that connects the slip boundary condition with the stress at the wall. Finally, a dynamic procedure for the slip coefficients is formulated, providing a dynamic slip wall model free of a priori specified coefficients. The performance of the proposed dynamic wall model is tested in a series of LES of turbulent channel flow at varying Reynolds numbers, non-equilibrium three-dimensional transient channel flow and a zero-pressure-gradient flat-plate turbulent boundary layer. The results show that the dynamic wall model is able to accurately predict one-point turbulence statistics for various flow configurations, Reynolds numbers and grid resolutions.

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Sun, Qian, Yonghong Wu, Lishan Liu, and B. Wiwatanapataphee. "Solution of Time Periodic Electroosmosis Flow with Slip Boundary." Abstract and Applied Analysis 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/789147.

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Recent research confirms that slip of a fluid on the solid surface occurs at micrometer scale. Slip on solid surface may cause the change of interior material deformation which consequently leads to the change of velocity profile and stress field. This paper concerns the time periodic electroosmotic flow in a channel with slip boundary driven by an alternating electric field, which arises from the study of particle manipulation and separation such as flow pumping and mixing enhancement. Although exact solutions to various flow problems of electroosmotic flows under the no-slip condition have been obtained, exact solutions for problems under slip boundary conditions have seldom been addressed. In this paper, an exact solution is derived for the time periodic electroosmotic flow in two-dimensional straight channels under slip boundary conditions.

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23

Le, Nam TP, Nam H. Tran, Thoai N. Tran, and Toan T. Tran. "New slip boundary condition in high-speed rarefied gas flow simulations." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 3 (2019): 840–56. http://dx.doi.org/10.1177/0954410019886955.

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In this paper, we propose a new slip boundary condition in hypersonic gas flow simulations. It is derived by considering the Langmuir isotherm adsorption into the Kaniadarkis et al. model of the kinetic theory of gas. Moreover, the motion of the adsorbed molecules over the surface (i.e. surface diffusion) is considered for the calculation of the mean free path in new slip condition. Three aerodynamic configurations are selected for evaluating new slip condition such as (1) the sharp-leading-edge flat plate, (2) circular cylinder in cross-flow, and (3) the sharp 25°–55° biconic cases. Hypersonic gas flows have the Mach number ranging from 6.1 to 15.6, and the working gases are argon and nitrogen. The simulation results show that new slip condition predicts better slip velocity than the Maxwell slip condition and gives good agreement with the direct simulation Monte-Carlo data for all cases considered in the present work.

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Baranovskii, Evgenii S. "Exact Solutions for Non-Isothermal Flows of Second Grade Fluid between Parallel Plates." Nanomaterials 13, no. 8 (2023): 1409. http://dx.doi.org/10.3390/nano13081409.

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In this paper, we obtain new exact solutions for the unidirectional non-isothermal flow of a second grade fluid in a plane channel with impermeable solid walls, taking into account the fluid energy dissipation (mechanical-to-thermal energy conversion) in the heat transfer equation. It is assumed that the flow is time-independent and driven by the pressure gradient. On the channel walls, various boundary conditions are stated. Namely, we consider the no-slip conditions, the threshold slip conditions, which include Navier’s slip condition (free slip) as a limit case, as well as mixed boundary conditions, assuming that the upper and lower walls of the channel differ in their physical properties. The dependence of solutions on the boundary conditions is discussed in some detail. Moreover, we establish explicit relationships for the model parameters that guarantee the slip (or no-slip) regime on the boundaries.

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KITRON-BELINKOV, MYRA, AMY NOVICK-COHEN, and NADAV LIRON. "A SLIP CONDITION BASED ON MINIMAL ENERGY DISSIPATION." Mathematical Models and Methods in Applied Sciences 06, no. 04 (1996): 467–80. http://dx.doi.org/10.1142/s0218202596000171.

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An intrinsic difficulty arises when solving Stokes equations in Ω ⊂ ℝ2 when the boundary conditions on the velocity are discontinuous: the solution is physically unacceptable since the force exerted by the fluid on the boundary is logarithmically singular. To illustrate this phenomena, we present an explicit solution in which the logarithmic singularity appears in a particularly simple form. A common method of avoiding the appearance of these singular forces is via an alteration of the boundary velocity profile in the vicinity of the discontinuity. However, there is no obvious physical criterion according to which the velocity profile along the boundary should be chosen. We consider a possible physically motivated criterion based on minimal energy dissipation. We prove the existence of a unique minimizing profile and demonstrate that the resultant velocity field does indeed exert a finite force along the boundary. Lastly, the minimizing profile is calculated numerically and the effect of free parameters is considered.

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Fortier, Alicia E., and Richard F. Salant. "Numerical Analysis of a Journal Bearing With a Heterogeneous Slip/No-Slip Surface." Journal of Tribology 127, no. 4 (2005): 820–25. http://dx.doi.org/10.1115/1.2033897.

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The no-slip boundary condition is part of the foundation of the traditional lubrication theory. It states that fluid adjacent to a solid boundary has zero velocity relative to the solid surface. For most practical applications, the no-slip boundary condition is a good model for predicting fluid behavior. However, recent experimental research has found that for certain engineered surfaces the no-slip boundary condition is not valid. Measured velocity profiles show that slip occurs at the interface. In the present study, the effect of an engineered slip/no-slip surface on journal bearing performance is examined. A heterogeneous pattern, in which slip occurs in certain regions and is absent in others, is applied to the bearing surface. Fluid slip is assumed to occur according to the Navier relation. Analysis is performed numerically using a mass conserving algorithm for the solution of the Reynolds equation. Load carrying capacity, side leakage rate, and friction force are evaluated. In addition, results are presented in the form of Raimondi and Boyd graphs. It is found that the judicious application of slip to a journal bearing’s surface can lead to improved bearing performance.

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Zampogna, Giuseppe A., Jacques Magnaudet, and Alessandro Bottaro. "Generalized slip condition over rough surfaces." Journal of Fluid Mechanics 858 (November 6, 2018): 407–36. http://dx.doi.org/10.1017/jfm.2018.780.

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A macroscopic boundary condition to be used when a fluid flows over a rough surface is derived. It provides the slip velocity $\boldsymbol{u}_{S}$ on an equivalent (smooth) surface in the form $\boldsymbol{u}_{S}=\unicode[STIX]{x1D716}{\mathcal{L}}\boldsymbol{ : }{\mathcal{E}}$, where the dimensionless parameter $\unicode[STIX]{x1D716}$ is a measure of the roughness amplitude, ${\mathcal{E}}$ denotes the strain-rate tensor associated with the outer flow in the vicinity of the surface and ${\mathcal{L}}$ is a third-order slip tensor arising from the microscopic geometry characterizing the rough surface. This boundary condition represents the tensorial generalization of the classical Navier slip condition. We derive this condition, in the limit of small microscopic Reynolds numbers, using a multi-scale technique that yields a closed system of equations, the solution of which allows the slip tensor to be univocally calculated, once the roughness geometry is specified. We validate this generalized slip condition by considering the flow about a rough sphere, the surface of which is covered with a hexagonal lattice of cylindrical protrusions. Comparisons with direct numerical simulations performed in both laminar and turbulent regimes allow us to assess the validity and limitations of this condition and of the mathematical model underlying the determination of the slip tensor ${\mathcal{L}}$.

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Geeta and Siddiqui S.U. "Effect of Slip velocity on Blood Flow in Catheterized Tapered Artery." Journal of Progressive Research in Mathematics 15, no. 2 (2019): 2594–608. https://doi.org/10.5281/zenodo.3974057.

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Effect of slip velocity on blood flow through an arterial stenosis which is developed along a tapering wall is studied here. A uniform catheter is inserted in a stenosed tube. Blood is assumed to behave like Newtonian fluid. No slip as well as slip condition is taken in the present paper, at the arterial wall a velocity slip condition is employed and a no slip at the catheter boundary. Analytic expressions are obtained for different flow parameters and their behavior discussed through graphs. For the numerical solution of the problem, which is described by NavierStokes equations with appropriate boundary conditions, the Perturbation method is adopted. It is found that due to the introduction of an axial slip velocity and flow rate increases but wall shear stress decreases. The effect of tapering is also seen in the present model.

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Mallea-Zepeda, Exequiel, Eber Lenes, and Elvis Valero. "Boundary Control Problem for Heat Convection Equations with Slip Boundary Condition." Mathematical Problems in Engineering 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/7959761.

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We analyze an optimal boundary control problem for heat convection equations in a three-dimensional domain, with mixed boundary conditions. We prove the existence of optimal solutions, by considering boundary controls for the velocity vector and the temperature. The analyzed optimal control problem includes the minimization of a Lebesgue norm between the velocity and some desired field, as well as the temperature and some desired temperature. By using the Lagrange multipliers theorem we derive an optimality system. We also give a second-order sufficient condition.

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Honig, C. D. F., and W. A. Ducker. "No-slip hydrodynamic boundary condition for hydrophilic particles." "Proceedings" of "OilGasScientificResearchProjects" Institute, SOCAR, no. 3 (June 30, 2011): 73–77. http://dx.doi.org/10.5510/ogp20110300086.

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31

Wang, Wei Dong, Xiang Yu Niu, Kang Qi Fan, and Qing Yi Wang. "Stokes' Second Problem with Velocity Slip Boundary Condition." Key Engineering Materials 483 (June 2011): 287–92. http://dx.doi.org/10.4028/www.scientific.net/kem.483.287.

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The damping effect of microfluidics has great effect on the dynamic characteristics of MEMS devices. Based on the separation of variables and the integral transform methods, the Stokes' second problem is solved at the microscale velocity slip boundary condition and the analytical solution for velocity distribution is obtained. Furthermore, the expression of the penetration depth is gotten for Stokes model in this article. Through analysis, it’s found that due to the effect of the microscale velocity slip boundary condition, the velocity oscillation amplitude and the penetration depth have been reduced. Then the shear stress, the damping force and elastic force on the plate have been investigated. It’s shown that both the elastic coefficient and the damping coefficient increases as the oscillation frequency rises.

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32

Jeong, Jae-Tack. "Slip boundary condition on an idealized porous wall." Physics of Fluids 13, no. 7 (2001): 1884–90. http://dx.doi.org/10.1063/1.1373680.

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Joshi, Yogesh M., and Morton M. Denn. "Planar contraction flow with a slip boundary condition." Journal of Non-Newtonian Fluid Mechanics 114, no. 2-3 (2003): 185–95. http://dx.doi.org/10.1016/s0377-0257(03)00151-4.

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Hayat, T., Masood Khan, and M. Ayub. "On non-linear flows with slip boundary condition." Zeitschrift für angewandte Mathematik und Physik 56, no. 6 (2005): 1012–29. http://dx.doi.org/10.1007/s00033-005-4006-6.

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Prabhakara, Sandeep, and M. D. Deshpande. "The no-slip boundary condition in fluid mechanics." Resonance 9, no. 5 (2004): 61–71. http://dx.doi.org/10.1007/bf02834016.

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Prabhakara, Sandeep, and M. D. Deshpande. "The no-slip boundary condition in fluid mechanics." Resonance 9, no. 4 (2004): 50–60. http://dx.doi.org/10.1007/bf02834856.

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Tuck, E. O., and A. Kouzoubov. "A laminar roughness boundary condition." Journal of Fluid Mechanics 300 (October 10, 1995): 59–70. http://dx.doi.org/10.1017/s0022112095003600.

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A modified slip boundary condition is obtained to represent the effects of small roughness-like perturbations to an otherwise-plane fixed wall which is acting as a boundary to steady laminar flow of a viscous fluid. In its simplest form, for low local Reynolds number and small roughness slope, this boundary condition involves a constant apparent backflow at the mean surface or, equivalently, represents a shift of the apparent plane boundary toward the flow domain. Extensions of the theory are also made to include finite local Reynolds number and finite roughness slope.

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38

Jauhri, Shefali, and Upendra Mishra. "Dual Solutions of EMHD Nanofluid at Stretching Sheet with Mixed Convection Slip Boundary Condition." International Journal of Heat and Technology 39, no. 6 (2021): 1887–96. http://dx.doi.org/10.18280/ijht.390624.

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In this paper stagnation boundary layer flow of nanofluid with mixed convection heat and mass transfer with Electrical Magneto Hydrodynamic (EMHD) effects over a second-order momentum slip boundary condition have been mathematically analysed. The governing equations are transformed by similarity variable and the problem becomes coupled third-order nonlinear coupled differential equations. We use fourth-order Runge Kuta method and shooting technique to find the solution. The effect of second-order momentum slip condition with linear thermal slip condition has determined. Variation of all nano energy conversion parameters depends on different factors has shown graphically. Some of the parameters possesses dual solution at different values of second-order velocity slip parameter (β1&β2).

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Wang, Li-li, Qing-liang Zeng, and Xin Zhang. "Influence of Spiral Angle on the Performance of Spiral Oil Wedge Sleeve Bearing." International Journal of Rotating Machinery 2018 (June 5, 2018): 1–7. http://dx.doi.org/10.1155/2018/5051794.

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Spiral angel is an important structure parameter of spiral oil wedge sleeve bearing, which produces greater impact on bearing performance. Based on JFO boundary condition, the generalized Reynolds equations considering four slip conditions are established. Using the concept of partial derivatives, stiffness and damping coefficients of sleeve bearing are calculated. The results show that carrying capacity and friction drag of oil film decrease, temperature rise decreases first and then increases, and end leakage rate, stiffness, and damping coefficients generally increase first and then decrease with the increase of spiral angle. The carrying capacity, friction drag, temperature rise, stiffness, and damping coefficients are smaller and the end leakage rate is higher considering wall slip and JFO condition compared with reckoning with no slip and Reynolds boundary condition.

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FUJII, Takehiro, Takeshi OMORI, and Takeo KAJISHIMA. "The immersed boundary projection method for the Navier slip boundary condition." Proceedings of the Fluids engineering conference 2019 (2019): OS2–25. http://dx.doi.org/10.1299/jsmefed.2019.os2-25.

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Zhu, Yingxi, and Steve Granick. "No-Slip Boundary Condition Switches to Partial Slip When Fluid Contains Surfactant." Langmuir 18, no. 26 (2002): 10058–63. http://dx.doi.org/10.1021/la026016f.

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Tan, Zhen, Hai-tao Qi, and Xiao-yun Jiang. "Electroosmotic flow of Eyring fluid in slit microchannel with slip boundary condition." Applied Mathematics and Mechanics 35, no. 6 (2014): 689–96. http://dx.doi.org/10.1007/s10483-014-1822-6.

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Hou, J. S., M. H. Holmes, W. M. Lai, and V. C. Mow. "Boundary Conditions at the Cartilage-Synovial Fluid Interface for Joint Lubrication and Theoretical Verifications." Journal of Biomechanical Engineering 111, no. 1 (1989): 78–87. http://dx.doi.org/10.1115/1.3168343.

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The objective of this study is to establish and verify the set of boundary conditions at the interface between a biphasic mixture (articular cartilage) and a Newtonian or non-Newtonian fluid (synovial fluid) such that a set of well-posed mathematical problems may be formulated to investigate joint lubrication problems. A “pseudo-no-slip” kinematic boundary condition is proposed based upon the principle that the conditions at the interface between mixtures or mixtures and fluids must reduce to those boundary conditions in single phase continuum mechanics. From this proposed kinematic boundary condition, and balances of mass, momentum and energy, the boundary conditions at the interface between a biphasic mixture and a Newtonian or non-Newtonian fluid are mathematically derived. Based upon these general results, the appropriate boundary conditions needed in modeling the cartilage-synovial fluid-cartilage lubrication problem are deduced. For two simple cases where a Newtonian viscous fluid is forced to flow (with imposed Couette or Poiseuille flow conditions) over a porous-permeable biphasic material of relatively low permeability, the well known empirical Taylor slip condition may be derived using matched asymptotic analysis of the boundary layer at the interface.

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Guo, Wenqiang, and Guoxiang Hou. "Three-Dimensional Simulations of Anisotropic Slip Microflows Using the Discrete Unified Gas Kinetic Scheme." Entropy 24, no. 7 (2022): 907. http://dx.doi.org/10.3390/e24070907.

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The specific objective of the present work study is to propose an anisotropic slip boundary condition for three-dimensional (3D) simulations with adjustable streamwise and spanwise slip length by the discrete unified gas kinetic scheme (DUGKS). The present boundary condition is proposed based on the assumption of nonlinear velocity profiles near the wall instead of linear velocity profiles in a unidirectional steady flow. Moreover, a 3D corner boundary condition is introduced to the DUGKS to reduce the singularities. Numerical tests validate the effectiveness of the present method, which is more accurate than the bounce-back and specular reflection slip boundary condition in the lattice Boltzmann method. It is of significance to study the lid-driven cavity flow due to its applications and its capability in exhibiting important phenomena. Then, the present work explores, for the first time, the effects of anisotropic slip on the two-sided orthogonal oscillating micro-lid-driven cavity flow by adopting the present method. This work will generate fresh insight into the effects of anisotropic slip on the 3D flow in a two-sided orthogonal oscillating micro-lid-driven cavity. Some findings are obtained: The oscillating velocity of the wall has a weaker influence on the normal velocity component than on the tangential velocity component. In most cases, large slip length has a more significant influence on velocity profiles than small slip length. Compared with pure slip in both top and bottom walls, anisotropic slip on the top wall has a greater influence on flow, increasing the 3D mixing of flow. In short, the influence of slip on the flow field depends not only on slip length but also on the relative direction of the wall motion and the slip velocity. The findings can help in better understanding the anisotropic slip effect on the unsteady microflow and the design of microdevices.

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Wang, Yun-Lei, Jiu-Hui Wu, Mu-Ming Hao, and Lu-Shuai Xu. "Improved hydrodynamic performance of liquid film seal by considering boundary slip and cavitation." Industrial Lubrication and Tribology 71, no. 9 (2019): 1108–15. http://dx.doi.org/10.1108/ilt-03-2019-0088.

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Purpose The purpose of this paper is to investigate the effect of boundary slip on hydrodynamic performance of liquid film seal considering cavitation. Design/methodology/approach A mathematical model of liquid film seal with slip surface was established based on the Navier slip model and Jakobsson–Floberg–Olsson (JFO) boundary condition. Liquid film governing equation was discretized by the finite difference method and solved by the SOR relaxation iterative algorithm and the hydrodynamic performance parameters of liquid film seal were obtained considering boundary slip and cavitation. Findings The results indicate that the values of performance parameters are affected significantly by the slip length under the condition of high speed and low differential pressure. Originality/value The performances of liquid film seal are investigated considering slip surface and cavitation. The results presented in the study are expected to provide a theoretical basis to improve the design method of liquid film seal.

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46

Afify, Ahmed A. "The Influence of Slip Boundary Condition on Casson Nanofluid Flow over a Stretching Sheet in the Presence of Viscous Dissipation and Chemical Reaction." Mathematical Problems in Engineering 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/3804751.

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The impacts of multiple slips with viscous dissipation on the boundary layer flow and heat transfer of a non-Newtonian nanofluid over a stretching surface have been investigated numerically. The Casson fluid model is applied to characterize the non-Newtonian fluid behavior. Physical mechanisms responsible for Brownian motion and thermophoresis with chemical reaction are accounted for in the model. The governing nonlinear boundary layer equations through appropriate transformations are reduced into a set of nonlinear ordinary differential equations, which are solved numerically using a shooting method with fourth-order Runge-Kutta integration scheme. Comparisons of the numerical method with the existing results in the literature are made and an excellent agreement is obtained. The heat transfer rate is enhanced with generative chemical reaction and concentration slip parameter, whereas the reverse trend is observed with destructive chemical reaction and thermal slip parameter. It is also noticed that the mass transfer rate is boosted with destructive chemical reaction and thermal slip parameter. Further, the opposite influence is found with generative chemical reaction and concentration slip parameter.

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47

Jha, Basant K., and Zainab Sa’id Yunus. "Transient Flow Through a Porous Channel with Ramped Pressure Gradient and Velocity Slip Boundary Condition." International Journal of Applied Mechanics and Engineering 27, no. 1 (2022): 78–90. http://dx.doi.org/10.2478/ijame-2022-0006.

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Abstract A transient flow formation of an incompressible fluid through a horizontal porous channel assuming a ramped pressure gradient is considered with the velocity slip boundary conditions. The flow is a laminar flow caused by ramped pressure gradient along the flow direction. The equation governing the flow is modeled, and solved by the Laplace transformation technique to obtain a semi-analytical solution under slip boundary conditions. It was noted that the flow velocity increases as the slip parameter is increased.

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Chen, Lei, Xuezeng Zhao, and Yunlu Pan. "Establishment of a Standard Method for Boundary Slip Measurement on Smooth Surfaces Based on AFM." Applied Sciences 9, no. 7 (2019): 1453. http://dx.doi.org/10.3390/app9071453.

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Typically, it is difficult to analyze and design a micro/nanofluid system, and the design process cannot follow the traditional law of hydrodynamics. The boundary condition is very important in the applications of a micro/nanofluid system. The existence of boundary slip can reduce the hydrodynamic resistance and enhance fluid flow. How to accurately determine the dynamic boundary conditions is increasingly concerned by researchers. Atomic force microscope (AFM) is proven to be the most advanced experimental instrument for studying the characteristics of the surface and the interaction interface. Most studies on the application of atomic force microscopy to the measurement of the boundary slip do not describe a systematic standard process, leading to many differences in the measurement results. In this paper, a standard process of measuring slip on smooth and flat surfaces is developed, including the data processing methods that minimize the interference factors in the original data as well as simplify the data expression. Thus, the boundary slip can be obtained more easily and accurately.

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Akkaya, Volkan Ramazan, and Ilyas Kandemir. "Event-Driven Molecular Dynamics Simulation of Hard-Sphere Gas Flows in Microchannels." Mathematical Problems in Engineering 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/842837.

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Classical solution of Navier-Stokes equations with nonslip boundary condition leads to inaccurate predictions of flow characteristics of rarefied gases confined in micro/nanochannels. Therefore, molecular interaction based simulations are often used to properly express velocity and temperature slips at high Knudsen numbers (Kn) seen at dilute gases or narrow channels. In this study, an event-driven molecular dynamics (EDMD) simulation is proposed to estimate properties of hard-sphere gas flows. Considering molecules as hard-spheres, trajectories of the molecules, collision partners, corresponding interaction times, and postcollision velocities are computed deterministically using discrete interaction potentials. On the other hand, boundary interactions are handled stochastically. Added to that, in order to create a pressure gradient along the channel, an implicit treatment for flow boundaries is adapted for EDMD simulations. Shear-Driven (Couette) and Pressure-Driven flows for various channel configurations are simulated to demonstrate the validity of suggested treatment. Results agree well with DSMC method and solution of linearized Boltzmann equation. At low Kn, EDMD produces similar velocity profiles with Navier-Stokes (N-S) equations and slip boundary conditions, but as Kn increases, N-S slip models overestimate slip velocities.

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FU, XIN, BAOMING LI, JUNFENG ZHANG, FUZHI TIAN, and DANIEL Y. KWOK. "ELECTROKINETIC SLIP FLOW OF MICROFLUIDICS IN TERMS OF STREAMING POTENTIAL BY A LATTICE BOLTZMANN METHOD: A BOTTOM-UP APPROACH." International Journal of Modern Physics C 18, no. 04 (2007): 693–700. http://dx.doi.org/10.1142/s0129183107010954.

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In traditional computational fluid dynamics, the effect of surface energetics on fluid flow is often ignored or translated into an arbitrary selected slip boundary condition in solving the Navier-Stokes equation. Using a bottom-up approach, we show in this paper that variation of surface energetics through intermolecular theory can be employed in a lattice Boltzmann method to investigate both slip and non-slip phenomena in microfluidics in conjunction with the description of electrokinetic phenomena for electrokinetic slip flow. Rather than using the conventional Navier-Stokes equation with a slip boundary condition, the description of electrokinetic slip flow in microfluidics is manifested by the more physical solid-liquid energy parameters, electrical double layer and contact angle in the mean-field description of the lattice Boltzmann method.

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Journal articles on the topic 'Slip boundary condition'

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