The steady, coaxial flow in which two immiscible, incompressible fluids of differing densities move past each other slowly in a vertical cylindrical tube has a continuum of possibilities due to the arbitrariness of the interface between the fluids. By invoking the presence of surface tension to at least restrict the shape of any interface to that of a circular arc or full circle, we consider th...

An azimuthally symmetric radially sheared azimuthal flow is driven by a nondiffusive, or residual, turbulent stress localized to a narrow annular region at the boundary of a cylindrical magnetized helicon plasma device. A no-slip condition, imposed by ion-neutral flow damping outside the annular region, combined with a diffusive stress arising from turbulent and collisional viscous damping in t...

In this article, one-phase and three dimensional computational fluid dynamics analysis was utilized to investigate the effect of annular field pattern of proton exchange membrane fuel cells (PEMFC) with different geometry on the performances and species distribution. This computational fluid dynamics code is used for solving the equation in single domain namely the flow field, the mass conserva...

A mathematical analysis has been carried out for the axial flow of a Bingham plastic fluid, in the Concentric Cylinder Viscometer which consists of a cylindrical sample holder (the cup) and a cylindrical spindle (the bob) coaxial with the cup. The fluid to be tested flows through the annular gap of the cup and the bob system, sheared by the rotation of the inner cylinder, while the outer cy...

In this work we propose an effective viscosity criterion for the stabilization of annular gas-liquid and liquid-particle flows and an inertial mechanism which drives waves into slugs in slugging gas-liquid flows. Annular flow is stable when the fluid having the higher effective viscosity occupies the core region and the lower viscosity fluid is the annulus. The eddy viscosity criterion is shown...

In the present study, non-Newtonian flow in annular pipe is considered. The analytical solution for velocity and temperature fields is presented while entropy generation due to fluid friction and heat transfer is formulated. The third grade fluid with constant properties is accommodated in the analysis. It is found that reducing non-Newtonian parameter increases maximum velocity magnitude and m...

A flow visualization study was carried out for boiling in a rectangular channel filled with and without metallic random porous media. Four main patterns are observed as intermittent slug-churn flow, churn-annular annular-mist mist regimes. These clearly classified based on the high-speed images of flow. The results pattern map according to mass rate were presented using saturation temperatures ...