Search results for "enclosure"

Influence of a Magnetic Field on Liquid Metal Free Convection in an Internally Heated Cubic Enclosure

2002

The buoyancy‐driven magnetohydrodynamic flow in a cubic enclosure was investigated by three‐dimensional numerical simulation. The enclosure was volumetrically heated by a uniform power density and cooled along two opposite vertical walls, all remaining walls being adiabatic. A uniform magnetic field was applied orthogonally to the gravity vector and to the temperature gradient. The Prandtl number was 0.0321 (characteristic of Pb–17Li at 300°C), the Rayleigh number was 104, and the Hartmann number was made to vary between 0 and 2×103. The steady‐state Navier–Stokes equations, in conjunction with a scalar transport equation for the fluid's enthalpy and with the Poisson equation for the electr…

Computation of MHD buoyant flows at low Pr in a cubic enclosure with a full resolution of the Hartmann layers

2002

A vorticity based aeroacoustic prediction for the noise emission of a low-speed turbulent internal flow

2003

Abstract Turbulent internal flows are known to generate intense noise as well as surface pressure fluctuations. Numerically predicting the noise emission near the prescribed boundaries requires that the sound-generating turbulent flow be adequately represented and described. The k – e method provides a promising tool for obtaining the unsteady characteristics of a realistic turbulent flow interacting with a rectangular flat plate undergoing “ground effect”. The far-field acoustic calculation is facilitated by the Kambe model (from Lighthill’s theory) and an original post-processor has been developed to determine the far-field spectra and the source term characteristics. In pre-processed tur…

The spatial evaluation of the radiative human body heat exchanges: An effective contribution for limiting energy consumption and achieving better ind…

2018

Abstract Radiative heat exchanges inside buildings remarkably affect the thermal balance of the human body in confined spaces and the related thermal comfort sensations of people. The mean radiant temperature is an important component of this balance. Unfortunately, it is usually computed by means of too simplified relationships, which significantly influence the comfort evaluations. Such simplified approaches are also accountable for a less effective design of HVAC systems which, in turn, could result in high energy consumption in the climatization of buildings. However, an accurate evaluation of the mean radiant temperature, especially when high intensity sources are present in a given in…

Superconductive and insulating inclusions for linear and non-linear conductivity equations

2015

We detect an inclusion with infinite conductivity from boundary measurements represented by the Dirichlet-to-Neumann map for the conductivity equation. We use both the enclosure method and the probe method. We use the enclosure method to prove partial results when the underlying equation is the quasilinear $p$-Laplace equation. Further, we rigorously treat the forward problem for the partial differential equation $\operatorname{div}(\sigma\lvert\nabla u\rvert^{p-2}\nabla u)=0$ where the measurable conductivity $\sigma\colon\Omega\to[0,\infty]$ is zero or infinity in large sets and $1<p<\infty$.

L’ENCEINTE NÉOLITHIQUE DE CRAVANT HAUT DE BRÉVIANDE, COMMUNE DE DEUX-RIVIÈRES (YONNE)et la séquence chronologique du début du Néolithique autour de l…

2022

Die von J.-P. Delor anhand von Luftaufnahmen identifizierte Einhegung von Deux-Rivières (Cravant) war 1999 Gegenstand einer kurzen Sondierungskampagne. Sie ist von einer Palissade und möglicherweise einem Graben oder einer zweiten Palisade umgeben und umgrenzt ein ca. 1,5 ha großes Areal. Sie wurde durch den Bau der Rollbahn eines Militärflughafens, bei dem der Innenbereich teilweise abgetragen wurde, stark beschädigt. Das Fundmaterial gestattet keine genauere Datierung. Die seltenen Indizien legen eine Zuordnung zu der in der Region gut vertretenen Cerny-Kultur nahe. Der vorliegende Artikel bietet die Gelegenheit, eine Aktualisierung der chronologischen Sequenz des Sektors Yonne-Cure im 5.…

Lo spazio della cella: voci dal silenzio

2010

Brownian motion in trapping enclosures: Steep potential wells, bistable wells and false bistability of induced Feynman-Kac (well) potentials

2019

We investigate signatures of convergence for a sequence of diffusion processes on a line, in conservative force fields stemming from superharmonic potentials $U(x)\sim x^m$, $m=2n \geq 2$. This is paralleled by a transformation of each $m$-th diffusion generator $L = D\Delta + b(x)\nabla $, and likewise the related Fokker-Planck operator $L^*= D\Delta - \nabla [b(x)\, \cdot]$, into the affiliated Schr\"{o}dinger one $\hat{H}= - D\Delta + {\cal{V}}(x)$. Upon a proper adjustment of operator domains, the dynamics is set by semigroups $\exp(tL)$, $\exp(tL_*)$ and $\exp(-t\hat{H})$, with $t \geq 0$. The Feynman-Kac integral kernel of $\exp(-t\hat{H})$ is the major building block of the relaxatio…

Algorithms for the calculation of the view factors between human body and rectangular surfaces in parallelepiped environments

1992

Abstract The thermal comfort conditions for people in moderate thermal environments are subjected to spatial changes, depending on the radiative exchanges of the human body with the surrounding surfaces. Radiative thermal exchanges are notably accounted for by means of the “view factors” between a person in a given posture and the surface of the enclosure. These important parameters can be evaluated by means of a large set of graphs by Fanger, for rectangular surfaces. But the handling of graphs could lead to reading errors. In this paper a simple algorithm is presented, which is able to compute the required view factors. A validation, by means of a comparison against experimental data, is …

Modeling propagation for high-power cylindrical microwave applicators

2001

In this letter, the dispersion characteristics and energy configurations of a cylindrical partially filled waveguide or lossy multilayered rod shielded by a metallic enclosure are presented for several modes. These parameters are obtained by a numerical simulation based on the residues theory. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 192–195, 2001.