In this paper, we present an analytical method to investigate the behavior of a two degrees of freedom oscillator excited by dry friction. The system consists of two masses connected by linear springs. These two masses are in contact with a driving belt moving at a constant velocity. The contact forces between the masses and the belt are obtained from Coulomb’s friction laws. A set of periodic ...

We solve a Langevin equation, first studied by de Gennes, in which there is a solid-solid or dry friction force acting on a Brownian particle in addition to the viscous friction usually considered in the study of Brownian motion. We obtain both the time-dependent propagator of this equation and the velocity correlation function by solving the associated time-dependent Fokker-Planck equation. Ex...

The motion of an elastic body over a rough surface is simulated in one dimension using Newtonian dynamics. We drive the body by prescribing a constant velocity. We extract the friction force from the work done by the applied force in order to maintain the motion of the body. A positive amount of work is needed because energy is converted into the internal elastic degrees of freedom of the body....

Cross-corrugated triangular channels increase heat transfer in heat exchangers. The mixing effect increases the heat transfer coefficient at the surfaces. In this study, the fluid flow and heat transfer in a triangular corrugated channel are modeled under two constant heat fluxes and different Reynolds numbers. In order to validate, k-ω turbulence model is used. Also, the effect of magnetic fie...

A contact/friction isoparametric finite element for the analysis of connections between laminated composite plates is presented. The element is compatible with a three-dimensional plate element based on layer-wise constant shear theory. The contact/friction element is based on a simple regularization of the unilateral contact with an orthotropic Coulomb friction problem. Two different friction ...

The skin friction on a surface is a major concern by engineers. It is widely accepted that turbulent flow has higher friction than laminar flow due to the higher mixing in boundary layer. However, our new high order DNS found that the high friction is generated in a laminar zone in a transitional flow. Whenever the small length scales are generated, the velocity shear becomes very large in the ...

In many systems, the normal force at friction contacts is not constant, but instead is a function of the system's state variables. Examples include machine tools, friction dampers, brake systems and robotic contact with the environment. Friction at these contacts has been shown to possess dynamics associated with changes in normal force. In an earlier paper, the authors derived a critical value...

We present a molecular dynamics ~MD! study of a Brownian particle in a two-dimensional periodic potential. For a separable potential, the study of the diffusion constant along the symmetry directions reduces to two one-dimensional problems. In this case, our MD study agrees with the existing analytical results on the temperature and the friction (h) dependence of the diffusion constant (D). For...

The present investigation constitutes CFD analysis of the heat transmission phenomenon in a tube exchanger with Y-shaped insert triangular perforation. is accomplished by considering air as working fluid Reynolds number ranging from 3000 to 21,000. segment considered for consists circular 68 mm diameter and 1.5 m length. geometrical parameter perforation index (0%, 10%, 20%, 30%). constant flux...

Presented here is a novel technique for the in situ calibration and measurement of friction with the atomic force microscope that can be applied simultaneously with the normal force measurement. The method exploits the fact that the cantilever sits at an angle of about 10° to the horizontal, which causes the tip or probe to slide horizontally over the substrate as a normal force run is performe...