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In recent years, additive manufacturing (AM) has begun to displace traditional manufacturing techniques for specific applications. Notable benefits of AM include reduced times from design to product, an improved buy-tofly [...]

The flow and heat transfer of [Al.sub.2][O.sub.3]-water nanofluid in a channel partially filled with porous media is investigated numerically. The turbulence effect in the porous media is taken under consideration in this article. A simple case is simulated first to evaluate the accuracy of the results in comparison with the available data. The turbulent kinetic energy profile is investigated at a flow cross section. The results show that the maximum turbulent kinetic energy occurs in the clear fluid region in the vicinity of the porous media region. The turbulent kinetic energy is a decreasing function of the porosity of the porous medium. The effect of porosity on the variation of turbulent kinetic energy decreases with the increase in the porosity of the porous medium. The turbulent kinetic energy in clear fluid and porous media regions decreases with the increase in nanofluid concentration from 0.01 to 0.03, and it increases with the increase in nanofluid concentration from 0.03 to 0.05. The temperature of the nanofluid increases with the increase in the nanofluid concentration and decrease in the porosity of porous media. It is shown that for this case, with the increase in nanofluid concentration and porosity of porous media, the skin friction coefficient increases and the Nusselt number decreases. Key words: porous media, nanofluid, turbulence modelling, heat transfer, computational fluid dynamics. Nous etudions numeriquement le flot et le transfert de chaleur du nanofluide [Al.sub.2][O.sub.3]-eau dans un canal partiellement rempli d'un milieu poreux. Nous tenons compte ici de la turbulence dans le milieu poreux. Nous simulons d'abord un cas simple pour evaluer la precision des resultats en les comparant avec des donnees disponibles. Nous examinons le profil d'energie cinetique turbulente a une section transversale du flot. Les resultats montrent que le maximum de l'energie cinetique turbulente se produit dans la region du liquide coulant pres du milieu poreux et qu'elle est une fonction decroissante de la porosite du milieu poreux. L'effet de la porosite sur la variation de l'energie cinetique turbulente diminue avec l'augmentation de la porosite du milieu poreux. L'energie cinetique turbulente dans la region d'interface liquid-milieu poreux diminue avec l'augmentation de la concentration de nanoparticules de 0.01 a 0.03 et augmente ensuite avec l'augmentation de concentration de 0.03 a 0.05. La temperature du nanofluide augmente avec la concentration en nanoparticules et diminue avec la porosite du milieu poreux. Nous montrons que dans ce cas, avec l'augmentation de la concentration de nanoparticules et de la porosite du milieu, le frottement superficiel augmente et le nombre de Nusselt diminue. [Traduit par la Redaction] Mots-cles: milieux poreux, nanofluide, modelisation de la turbulence, transfert de chaleur, dynamique computationnelle des fluides., 1. Introduction The flow and heat transfer of fluid in porous media has many applications in several engineering processes, such as microelectronic cooling, chemical reactors, energy storage units, and heat [...]

We construct a stochastic interpretation of a generalized solution of the Cauchy problem for the simplest magneto-hydrodynamics system, namely, a system including the Burgers equation with a pressure due to a magnetic field. The probabilistic representation constructed in the paper can be used for numerical computations. Bibliography: 17 titles., UDC 519.2 1. Introduction The aim of this paper is to construct a stochastic model of the dynamics described by a system of nonlinear parabolic equations of the form [mathematical [...]

ABSTRACT The hurricane project at the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL) was established in 1970. By the mid-1970s pioneering research had led to the [...]

One of the first significant developments in wildfire modeling research was to introduce heat flux as wildfire line intensity (kW * [m.sup.-1]). This idea could be adapted to using weather station measurements, topography, and fuel properties to estimate rate of fire spread, shape, and intensity. This review will present, in an accessible manner, the next evolution in wildfire models. The new generation models use mechanistic combustion models and large-eddy simulation (LES) to define the flaming combustion and the mechanism of rate of spread. These wildfire models are then coupled to a computational fluid dynamics (CFD) or mesoscale weather model. In other words, wildfire models become weather and climate models with add-in fuel and terrain models. These coupled models can use existing fire and weather physics or developed noncoupled models with a coupling mechanism. These models are tailored for specific spatial and temporal scales. Key words: wildfire, fuel, fire behavior, WRF-FIRE, FIRETEC, WFDS, CAWFE, ForeFire/Meso-NH, ARPS/DEVS-FIRE, finite difference, finite volume. Resume : Un des premiers developpements en recherche sur la modelisation des feux de foret a ete d'introduire le flux de chaleur en tant qu'intensite de la ligne de feu (kW * [m.sup.-1]). Cette idee pouvait etre adaptee pour utiliser les mesures des stations meteorologiques, la topographie et les proprietes des combustibles pour estimer la forme, l'intensite et le taux de propagation du feu. Cette synthese presente de facon accessible la prochaine evolution dans les modeles de feux de foret. La nouvelle generation de modeles utilise des modeles de combustion mecanistes et la simulation de grands ecoulements tourbillonnants (LES) pour definir la combustion accompagnee de flammes et le mecanisme du taux de propagation. Ces modeles de feux de foret sont ensuite couples a un modele de dynamique des fluides numerique (CFD) ou un modele meteorologique meso-echelle. En d'autres mots, les modeles de feux de foret deviennent des modeles meteorologiques et climatiques avec des modeles complementaires de combustibles et de terrain. Ces modeles couples peuvent utiliser un feu en cours et la physique meteorologique ou des modeles non couples avec un mecanisme de couplage. Ces modeles sont adaptes a des echelles spatiales et temporelles specifiques. [Traduit par la Redaction] Mots-cles: feu de foret, combustible, comportement du feu, modeles de simulation WRF-FIRE, FIRETEC, WFDS, CAWFE, ForeFire/ Meso-NH, ARPS/DEVS-FIRE, difference finie, volume fini., Introduction Traditionally, the wildfire behavior community has had a goal of predicting fire spread and flame length from easily measured variables, particularly fuel and surface weather variables. Early fire behavior [...]

By using the Lorentz factor as a viscosity term in Stokes' law for objects traveling in a vacuum, Mercury's perihelion precession and the Pioneer anomaly are directly and exactly solved, demonstrating that physical vacuum is a shear- thickening (dilatant) fluid. The modified Stokes' equation also correctly indicates that planetary orbits are stable (over trillions of years). This unexpected feature of physical vacuum may help in achieving quantum relativity and implies interesting consequences for various fields of modern physics. Key words: dilatant vacuum, vacuum hydrodynamics, Pioneer anomaly, perihelion precession, general relativity. En utilisant le facteur de Lorentz comme terme de viscosite dans la loi de Stokes pour des objets voyageant dans le vide, la precession du perihelie de Mercure et l'anomalie Pioneer sont directement et exactement solutionnees, demontrant que le vide est un fluide antithixotropique. L'equation modifiee de Stokes indique precisement que les orbites planetaires sont stables (sur des trillions d'annees). Cette caracteristique inattendue du vide physique peut aider a realiser la relativite quantique et introduit des consequences pour differents champs de la physique moderne. [Traduit par la Redaction] Mots-cles: vide antithixotropique, hydrodynamique du vide, anomalie Pioneer, precession du perihelie, relativite generale., 1. Introduction Some authors considered the possibility that the physical vacuum maybe a superfluid, a special Bose-Einstein condensate [1-9]. Here, by exactly solving two known anomalies, along with other correct [...]

Three-dimensional, non-isothermal, transient computational fluid dynamics simulations are conducted for rubber mixing with a set of two-wing rotors in a partially filled chamber. The main objective is to analyze the effect of different fill factors of rubber on dispersive and distributive mixing characteristics by simulating 15 revolutions of the rotors rotating at 20 rpm. 60%, 70%, 75%, and 80% are the four different fill factors chosen for the study. An Eulerian multiphase model is employed to simulate two different phases, rubber and air, and the volume of fluid technique is used to calculate the free surface between two phases, in addition to the continuity, momentum and Energy equations. To characterize non-Newtonian, highly viscous rubber, shear rate and temperature dependent Carreau-Yasuda model has been used. A set of more than 3,600 massless particles are injected after a certain period of time to calculate several quantities in terms of dispersive and distributive mixing. Both the Eulerian and Lagrangian results showed that, fill factors between 70% and 80% presented the most reasonable and efficient mixing scenario, thus exhibiting the best dispersive and distributive mixing characteristics combined., INTRODUCTION Rubber is the basic raw material for tire manufacturing process, which is mainly synthesized from petroleum byproducts [1]. Rubber can also be harvested naturally as a form of latex, [...]

We discuss connections between Fomenko invariants of Liouville foliations and asymptotic solutions of the Navier-Stokes equations that describe vortex structures in an incompressible fluid., UDC 514.8 To the anniversary of A. T. Fomenko 1. Introduction There exists an interesting connection between the topological theory of integrable Hamiltonian systems (this theory was developed by A. [...]