The dynamics of charged Coulomb grains in a plasma is numerically and analytically investigated. Analogous to recent experiments, it is assumed that the grains are trapped in an external parabolic field. Our simulations are based on a Langevin model, where the grain-plasma interaction is realized by a velocity-dependent friction coefficient and a velocity-independent diffusion coefficient. In a...

A known difficulty with using the Clauser chart method to determine the friction velocity in wall bounded flows is that it assumes, a priori, a logarithmic law for the mean velocity profile. Using both experimental and DNS data in the literature, this note explicitly shows how friction velocities obtained using the Clauser chart method can potentially mask subtle Reynolds-number-dependent behav...

Friction coefficient and wear rate of different steel materials are investigated and compared in this study. In order to do so, a pin on disc apparatus is designed and fabricated. Experiments are carried out when different types of disc materials such as stainless steel 314 (SS 314), stainless steel 202 (SS 202) and mild steel slide against stainless steel 314 (SS 314) pin. Experiments are cond...

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 ...

in this paper, least square method (lsm) and differential transformation method (dtm) are used to solve the problem of laminar nanofluid flow in a semi-porous channel in the presence of transverse magnetic field. due to existence some shortcomings in each method, a novel and efficient method named ls-dtm is introduced which omitted those defects and has an excellent agreement with numerical sol...

The objective of this PhD thesis was the study of friction in carbon nanotubes by analytical methods and molecular dynamics simulations. The goal of this research was to characterize the properties of friction in nanotubes and from a more general point of view the understanding of the microscopic origin of friction. Indeed, the relative simplicity of the system allows us to interpret more easil...

The Alpine Fault, New Zealand, is a major plate-bounding fault that accommodates 65-75% of the total relative motion between the Australian and Pacific plates. Here we present data on the hydrothermal frictional properties of Alpine Fault rocks that surround the principal slip zones (PSZ) of the Alpine Fault and those comprising the PSZ itself. The samples were retrieved from relatively shallow...

There has been plenty of observational evidence of cluster galaxy evolution such as the Butcher-Oemler effect and the morphology-density relation. However, it has been difficult to identify the origin of the cluster galaxy evolution. It has been simply difficult to trace the complicated process of galaxy evolution with several giga years of timescale, using the observation which only brings us ...

[1] Measurements of Eulerian flow velocity obtained within the swash zone on a relatively steep beach face (gradient 1:23) are compared with an extended ballistic swash model. The model only requires a friction factor, beach slope and terminal bore velocity as input. The following model predictions matched well with observations: (1) The maximum Eulerian flow velocity is the shoreline velocity ...

some physical properties such as geometrical, gravimetrical, frictional and aerodynamic features of seeds of desi chickpea and its splits were studied at a moisture content of 8.2 and 9.0% w., respectively from north-western of iran. geometrical and gravimetrical properties including the average length, width, thickness, the geometric mean of diameter, sphericity, 1000-seed weight, unit weight,...