In this article, we calculate the scalar form factors fππ(Q 2) and fKK(Q 2) within the framework of the light-cone QCD sum rules approach. The numerical value of fππ(Q 2) changes quickly with variation of Q2 near zero momentum transfer, while the fKK(Q 2) has rather good behavior at small momentum transfer. The value fKK(0) = 2.21 +0.35 −0.19GeV is compatible with the values from the leading or...

In this paper, flow and heat transfer of nanofluid through a converging or diverging channel with porous medium is investigated. The fluid constantly flows under the effect of magnetic field through the channel. The diverging/converging fluid motion is modeled using the momentum and energy equations. The influence of some parameters such as opening channel angle, Reynolds number and Darcy’s num...

Process control of a spray dryer that is usually used as the last step of production is very crucial in obtaining a quality standard product. To this end, predicting the effect of various operating and environmental parameters on product properties is essential. Modeling was done in microscopic and macroscopic scales by modifying the mass and heat transfer equations used in investigating the dr...

In this paper a numerical investigation is performed to study the effects of different nanofluids on convective heat transfer enhancement in a partitioned square cavity subject to different shapes of nanoparticle using water-SiO2 nanofluid. This study has been carried out to analyze the effects of SiO2 nanoparticle, its volumetric fraction between 2 and 4%, and nanoparticle shape (i.e. blades, ...

A self-contained theory of the domain wall dynamics in ferromagnets under finite electric current is presented. The current has two effects: one is momentum transfer, which is proportional to the charge current and wall resistivity (rho(w)); the other is spin transfer, proportional to spin current. For thick walls, as in metallic wires, the latter dominates and the threshold current for wall mo...

The fluid flow and heat transfer in a three-dimensional microchannel filled with Al2O3- water nanofluid is numerically investigated. The hybrid scheme is used to discretize the convection terms and SIMPLER algorithm is adopted to couple the velocity and pressure field in the momentum equations. The thermal and flow fields were analyzed using different volume fractions of n...

A mathematical model considering mass and momentum transfer was developed for simulation of ethanol dewatering via pervaporation process. The process involves removal of water from a water/ethanol liquid mixture using a dense polymeric membrane. The model domain was divided into two compartments including feed and membrane. For a description of water transport in ...

The fluid flow and heat transfer in a three-dimensional microchannel filled with Al2O3- water nanofluid is numerically investigated. The hybrid scheme is used to discretize the convection terms and SIMPLER algorithm is adopted to couple the velocity and pressure field in the momentum equations. The thermal and flow fields were analyzed using different volume fractions of n...

The first theory of wind-driven flow is that of Ekman, who assumed a uniform eddy viscosity and derived the velocity spiral that bears his name. Over the years, observations of wind stress and current have improved to the point that frictional momentum transfer in the upper ocean can be quantified. Observations of velocity spirals are reviewed to address such issues as the vertical structure an...

A one-dimensional vertical two-phase flow model for sedimentation-consolidation process is presented. The model is based on solving the continuity and momentum equations for both fluid and solid phases. In the non-cohesive case, the momentum transfer between the two phases is reduced to the drag force around a single particle modified to take the hindrance effects into account. In the cohesive ...