By integrating eeects of microscopic interactions between statisticaly self-similar fault surfaces, we succeeded in deriving a slip-and time-dependent fault constitutive law that rationally uniies the slip-dependent law and the rate-and state-dependent law (Aochi and Matsu'ura, 199881]). In this con-stitutive law the slip-weakening results from the abrasion of surface asperities that proceeds i...

Stick-slip friction was observed in articular cartilage under certain loading and sliding conditions and systematically studied. Using the Surface Forces Apparatus, we show that stick-slip friction can induce permanent morphological changes (a change in the roughness indicative of wear/damage) in cartilage surfaces, even under mild loading and sliding conditions. The different load and speed re...

This paper describes the results of two experiments that investigate relative motion between a surface and the fingertip (slip) as part of a larger program of research on “fingertip haptics.” The primary intent of both experiments is to evaluate the importance of relative motion with respect to perceiving surface velocity. The perception of surface velocity is crucial to dexterous control and o...

Molecular dynamics simulations are used to investigate the influence of molecular-scale surface roughness on the slip behavior in thin liquid films. The slip length increases almost linearly with the shear rate for atomically smooth rigid walls and incommensurate structures of the liquid/solid interface. The thermal fluctuations of the wall atoms lead to an effective surface roughness, which ma...

In a variety of applications, most notably microfluidics design, slip-based boundary conditions have been sought to characterize fluid flow over patterned surfaces. We focus on laminar shear flows over surfaces with periodic height fluctuations and/or fluctuating Navier scalar slip properties. We derive a general formula for the ‘effective slip’, which describes equivalent fluid motion at the m...

Effects of hydrophobic surface on skin-friction drag are investigated through direct numerical simulations of a turbulent channel flow. Hydrophobic surface is represented by a slip-boundary condition on the surface. When a slip-boundary condition is used in the streamwise direction, the skin-friction drag decreases and turbulence intensities and turbulence structures, near-wall streamwise vorti...

While propagation of dislocations in body centered cubic metals at low temperature is understood in terms of elementary steps on {110} planes, slip traces correspond often with other crystallographic or non-crystallographic planes. In the past, characterization of slip was limited to post-mortem electron microscopy and slip trace analysis on the sample surface. Here with in-situ Laue diffractio...

Abstract: The structure of natural tornadoes and simulated analogs are sensitive to the lower boundary condition for friction. Three-dimensional numerical simulations of storms require a choice for turbulence parameterizations and resolution of wind near the lower boundary. This article explores some of the consequences of choices of a surface drag coefficient on the structure of a mature simul...

We present an experimental study of a low-Reynolds number shear flow between two surfaces, one of which has a regular grooved texture augmented with a superhydrophobic coating. The combination reduces the effective fluid-surface contact area, thereby appreciably decreasing the drag on the surface and effectively changing the macroscopic boundary condition on the surface from no slip to limited ...

"Walking-Mode Maps", based on Slip/Non-Slip criteria, are proposed. Slip/Non-Slip criteria are expressed as follows: for a slip to occur: |F(h)/F(n)|(h) > or = mu(s) or |F(h)/F(n)|(t) > or = mu(s); for no slip to occur: |F(h)/F(n)|(h) < mu(s) or |F(h)/F(n)|(t) < mu(s). |F(h)/F(n)|(h) and |F(h)/F(n)|(t) are the maximum peak value of the traction coefficient at heel-strike and toe-off respectivel...