Recall that a rng is a ring which is possibly non-unital. In this note, we address the problem whether every finitely generated idempotent rng (abbreviated as irng) is singly generated as an ideal. It is well-known that it is the case for a commutative irng. We prove here it is also the case for a free rng on finitely many idempotents and for a finite irng. A relation to the Wiegold problem for...

Fast and accurate simulation of the outdoor airflow distribution is important for studying urban microclimate. In this paper, two pressure-correction schemes (i.e., NIPC NSPF) solving N-S equation item by are implemented in OpenFOAM their differences from PISO algorithm simulating around a single 1:1:2 bluff body analyzed. The RNG k-ε turbulence model chosen to study disturbance, while second-o...

The relative neighbourhood graph (RNG) of a set of n points on the plane is defined. The ability of the RNG to extract a perceptually meaningful structure from the set of points is briefly discussed and compared to that of two other graph structures: the minimal spanning tree (MST) and the Delaunay (Voronoi) triangulation (DT). It is shown that the RNG is a superset of the MST and a subset of t...

This paper presents experimental and computational investigation of the dispersion mechanisms of a passive-type tracer gas, done in the scaled, three-dimensional model of a street canyon. At a low wind speed of 1.67m/s and neutral atmospheric conditions, dispersion of pollutant has been investigated within an isolated street canyon at an aspect ratio of 1 for perpendicular wind orientation (90)...

In this paper, the behavior of the internal nozzle flow of a standard diesel fuel has been compared against a biodiesel fuel (soybean oil) at cavitating and non-cavitating conditions, using a homogeneous equilibriummodel. Themodel takes into account the compressibility of both phases (liquid and vapour) and use a barotropic equation of state which relates pressure and density to calculate the g...

This article presents heat transfer and fluid flow characteristics in a solar air heater (SAH) channel with multi V-type perforated baffles. The flow passage has an aspect ratio of 10. The relative baffle height, relative pitch, relative baffle hole position, flow attack angle, and baffle open area ratio are 0.6, 8.0, 0.42, 60 ̋, and 12%, respectively. The Reynolds numbers considered in the stud...

Superheaters are essential components in a coal-fired power plant because they keep the highest tube wall temperature points radiant boiler. The pressurized steam flowing superheater tubes is heated via thermal radiation and convection from combustion gas. To prevent bursting of caused by fatigue for stable safe operation, precisely predicting complex heat transfer characteristics, estimating l...

In this study, the local scour around tripods in random waves is numerically investigated. The seabed-tripod-fluid numerical model with an RNG k−ε turbulence built and validated. Following that, characteristics flow velocity distribution are analyzed using present model. Finally, a revised stochastic proposed to predict equilibrium depth, Seq, waves. results indicate that capable of depicting p...

In the present work are presented results from numerical simulations performed with the ANSYS-CFX code. It is studied a radial diffuser flow case, which is the main academic problem used to study the flow behavior on flat plate valves. The radial flow inside the diffuser has important behaviors such as the turbulence decay downstream and recirculation regions inside the valve flow channel due t...