ABSTRACT Dynamical friction arises from the interaction of a perturber and the gravitational wake it excites in the ambient medium. This interaction is usually derived assuming that the perturber has a constant velocity. In realistic situations, motion is accelerated as for instance by dynamical friction itself. Here, we study the effect of acceleration on the dynamical friction force. We chara...

Convective heat transfer and friction factor properties for periodic undulating channels are numerically investigated. The finite volume method (FVM) was used in the numerical study. Three different Reynolds averaged simulation (RANS) based turbulence models, shear stress transport SST k-ω transition model were compared with each other. Two used; first geometry is a sharp corrugated channel 30°...

in this study, stability of geosynthetic reinforced soil retaining walls investigated using plaxis code that is based on finite element method. the effects of axial stiffness, length and vertical space between geosynthetic layers, internal friction angle of soil wall and cohesion of foundation on deformations of wall and maximum axial force of geosynthetic have been investigated. results of ana...

this paper discusses the arching effect as the formation of a stable arch in granular materials. for this aim, a developed trapdoor apparatus is designed in order to investigate the arch dimensions in term of the internal friction angle, average size and base angle of materials. observations show that for all tested granular ensembles, width and height of the arch increase with an increase in t...

this work presents a numerical analysis of entropy generation in γ-shaped enclosure that was submitted to the natural convection process using a simple thermal lattice boltzmann method (tlbm) with the boussinesq approximation.  a 2d thermal lattice boltzmann method with 9 velocities, d2q9, is used to solve the thermal flow problem. the simulations are performed at a constant prandtl number (pr ...

A three-dimensional numerical simulation of flow through serpentine microchannels with designed roughness in form of obstructions placed along the channels walls is conducted here. CFD-ACE+ is used for the numerical simulations. The effect of the roughness height (surface roughness), geometry, Reynolds number on the friction factor is investigated. It is found that the friction factor increases...

In the present paper, an analysis was carried out to investigate effects of radiation on a free convection flow bounded by a vertical surface embedded in a porous medium with constant suction velocity. It was under the influence of uniform magnetic field in the presence of a homogenous chemical reaction and viscous dissipation with constant heat and mass flux. The non-dimensional governing equa...

In order to increase the efficiency of the conveyance of the granular solids, a new experimental set-up is designed. The test rig has longitudinal trapezoidal slots in its conveying pipes. Through experimentation, a correlation for friction factor in terms of solid mass flow rate, fluid flow rate and Froude number is presented. It is shown that the mixture friction factor for pipes with inn...

The widely used PASCO laboratory equipment is an excellent way to introduce students to many topics in physics. In one case, PASCO’s equipment may be too good! Various experiments exist for calculating the kinetic coefficient of friction by measuring the acceleration of a sliding object under some constant force. With ever more accurate equipment, such as electronic motion sensors, students are...