The understanding of the spreading of liquids on solid surfaces is an important challenge for contemporary physics. Today, the motion of the contact line formed at the intersection of two immiscible fluids and a solid is still subject to dispute. In this paper, a new picture of the dynamics of wetting is offered through an example of non-Newtonian slow liquid movements. The kinematics of liquid...

We propose a Langevin model with Coulomb friction. Through the analysis of the corresponding Fokker-Planck equation, we have obtained the steady velocity distribution function under the influence of the external field.

The understanding of the spreading of liquids on solid surfaces is an important challenge for contemporary physics. Today, the motion of the contact line formed at the intersection of two immiscible fluids and a solid is still subject to dispute. In this paper, a new picture of the dynamics of wetting is offered through an example of non-Newtonian slow liquid movements. The kinematics of liquid...

In 1883 Johannes von Kries published the theory of waterhammer in a study of blood flow in arteries. He derived the “Joukowsky formula” before Joukowsky (1898) and Frizell (1898) did. He considered skin friction in unsteady laminar flow and thus derived formulas for wave attenuation and line pack. The theory was confirmed by experimental results obtained in rubber hoses. In 1892 he published th...

We study the effects of temperature and sliding velocity on superlubricity in numerical simulations of the Frenkel-Kontorova model. We show that resonant excitations of the phonons in an incommensurate sliding body lead to an effective friction and to thermal equilibrium with energy distributed over the internal degrees of freedom. For finite temperature, the effective friction can be described...

Simulations of the kinetic friction due to a layer of adsorbed molecules between two crystalline surfaces are presented. The adsorbed layer naturally produces friction that is consistent with Amontons’ laws and insensitive to parameters that are not controlled in experiments. The kinetic friction rises logarithmically with velocity as in many experimental systems. Variations with potential para...

A model reference adaptive controller (MRAC) for compensating friction and payload uncertainties in a servopneumatic actuation system is presented in this paper. A friction model combining viscous and Coulomb friction is formulated within the framework of an adaptive controller. Due to the asymmetric nature of Coulomb friction in pneumatic piston actuators, a bi-directional Coulomb friction mod...

Nonlinearities degrade considerably performances in motion control systems. Nonlinear friction is a major source of many serious problems such as wear, tracking errors and limit cycles. There has been an extensive research activity dealing with the design of compensating techniques. The approaches cited in the litterature can be divided into: free model compensation or model based compensation ...

A nonlinear observer for estimation of lateral and longitudinal velocity of automotive vehicles is proposed, based on acceleration and yaw rate measurements in addition to wheel speed and steering angle measurements. Stability of the observer is proved in the form of input-to-state stability of the observer error dynamics, under an assumption on the friction model. This assumption is treated wi...

Melt produced by friction during earthquakes may act either as a coseismic fault lubricant or as a viscous brake. Here we estimate the dynamic shear resistance (tau(f)) in the presence of friction-induced melts from both exhumed faults and high-velocity (1.28 meters per second) frictional experiments. Exhumed faults within granitoids (tonalites) indicate low tau(f) at 10 kilometers in depth. Fr...