نتایج جستجو برای: friction theory

تعداد نتایج: 813640  

2007
N. C BELL H. S. WHEATER P. M. JOHNSTON N. C. Bell H. S. Wheater P. M. Johnston

Abstract Using the Imperial College laboratory catchment facility data from 96 experiments on a slightly-roughened varnished strip catchment (1 m x 9.925 m) are used to investigate the performance of numerical models of overland flow based on the kinematic wave approximation. A simple four-parameter model incorporates the Darcy-Weisbach laminar flow and Manning turbulent flow friction relations...

2011
Rui Liu

The seals are the important component of the aircraft engine to prevent leakage of gas or oil. Because the contact and friction problems have a great influence on the performance of the seals, the concept and theory of tribology is already widely applied in research and design processes of advanced seals. This report selected three kinds of representative seals which are co...

2013
Milad Radiom Chun Yang Weng Kong Chan

This paper presents an investigation into spreading dynamics and dynamic contact angle of TiO2-deionized water nanofluids. Two mechanisms of energy dissipation, (1) contact line friction and (2) wedge film viscosity, govern the dynamics of contact line motion. The primary stage of spreading has the contact line friction as the dominant dissipative mechanism. At the secondary stage of spreading,...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2012
J B Sokoloff

Persson's multiscale contact mechanics theory combined with a multiscale Brillouin-Prandtl-Tomlinson model is used to show that on the basis of these models "dry friction" [i.e., kinetic friction that remains at exceedingly small velocities (but still above the creep range) close to its value at higher velocities] should almost always occur for self-affine surfaces when the dominant interaction...

Journal: :Physical review letters 2013
A J Weymouth D Meuer P Mutombo T Wutscher M Ondracek P Jelinek F J Giessibl

Friction between two objects can be understood by the making, stretching, and breaking of thousands of atomic-scale asperities. We have probed single atoms in a nonisotropic surface [the H-terminated Si(100) surface] with a lateral force microscope operating in noncontact mode. We show that these forces are measurably different, depending upon the direction. Experimentally, these differences ar...

2000
Raffaele Cafiero Stefan Luding

We propose a mean field (MF) theory for a homogeneously driven granular gas of inelastic particles with Coulomb friction. The model contains three parameters, a normal restitution coefficient rn, a maximum tangential restitution coefficient r m t , and a Coulomb friction coefficient μ. The parameters can be tuned to explore a wide range of physical situations. In particular, the model contains ...

1999
Christophe Josserand

A 2-D version of the asymmetric exclusion model for granular sheared flows is presented. The velocity profile exhibits two qualitatively different behaviors, dependent on control parameters. For low friction, the velocity profile follows an exponential decay while for large friction the profile is more accurately represented by a Gaussian law. The phase transition occurring between these two be...

2011
I. A. Lyashenko A. V. Khomenko

A deterministic theory describing the behavior of an ultrathin lubricant film between two atomically-smooth solid surfaces is proposed. For the description of lubricant state the parameter of excess volume arising due to chaotization of solid medium structure in the course of melting is introduced. Thermodynamic and shear melting is described consistently. Dependences of friction force on tempe...

1998
Sarika Bhattacharyya Biman Bagchi

While the time dependence of the friction on a tagged particle in a dense liquid has been investigated in great detail, a similar analysis for the viscosity of the medium and the interrelationship between the two has not been carried out. This is despite the close relation always assumed, both in theoretical and experimental studies, between friction and viscosity. In this article a detailed st...

In this article the behavior of tetrahydrofuran (THF) + 2-alkanol namely 2-propanol, 2-butanol, 2-pentanol, 2-hexanol and 2-heptanol binary mixtures through the density and viscosity measurements have been studied as a function of composition and within the temperature range of 293.15–313.15 K. The excess molar volume, isobaric thermal expansivity, partial molar volumes, and viscosity deviation...

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