The optic ow eld is deened as preserving the intensity along ow-lines. Due to singularities in the image at xed time, poles are created in the optic ow eld. In this paper we describe the generic types of ow singularities and their generic interaction over time. In a general analytic ow eld, normally the topology is characterised by the points where the ow vanish again subdivided into repellers,...

In pipeline-riser systems, pressure fluctuations which result from the formation of large liquid slugs and gas surges due to operational changes or low mass flow rate from production wells and the profile of pipeline-riser systems often lead to trips at the inlet of the separator; and thereby, the problem causes a a loss of the production.In this study, on a sample deep-water oil field off the ...

Direct numerical simulation of turbulent flow behind a cylinder, wake flow, using the random vortex method for an incompressible fluid in two dimensions is presented. In the random vortex method, the primary variable is vorticity of the flow field. After generation on the cylinder wall, it is followed in two fractional time step in a Lagrangian system of coordinates, namely convection and diffu...

to simulate a new economical architecture for pem fuel cell and investigate the effectiveness of the introduced structure on the performance, computational fluid dynamics (cfd) code is used to solve the equations for a single domain of the cell namely: the flow field, the mass conservation, the energy conservation, the species transport, and the electric/ionic fields under the assumptions of st...

tellurium nanostructures have been prepared by physical vapor deposition method in a tube furnace. the experiments were carried out under argon gas flow at a pressure of 1 mbar. tellurium powder was evaporated by heating at 350°c and 430°c and was condensed on substrates at 110–250°c, in the downstream of argon gas flow. the products were characterized by field emission scanning electron micros...

Free convection flow in an enclosure filled with a congealing melt leads to the product with a nonuniform structure involving large grains. The convective flows are decreased by applying an appropriate magnetic field, obtaining uniform and small grain structures. In this work, using the finite volume method, we investigated the application of a magnetic field to the convective heat transfer and...