LEPTIAB

La Rochelle, France
La Rochelle, France

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Le Roux N.,French Scientific and Technical Center for Building | Le Roux N.,Institute for Radiological Protection and Nuclear Safety | Faure X.,French Scientific and Technical Center for Building | Inard C.,LEPTIAB | And 2 more authors.
Building and Environment | Year: 2012

To study mass transfers inside buildings equipped with ventilation systems, a methodology has been developed to carry out reduced-scale experiments for studying isothermal flows in a steady or a transient state. This methodology has been numerically and experimentally validated on simple configurations and applied to two reference configurations representative of nuclear facilities. The wind influence on mass transfers inside these configurations, in nominal, damaged (ventilation stopped) or accidental (internal overpressure) situations, has been studied by carrying out wind tunnel experiments. The objectives of this article are to present the scaling-down methodology and the main experimental results concerning the influence of wind on steady-state airflows inside the reduced-scale models. It is notably shown that wind effects can lead to a partial or a total loss of the pollutant containment inside buildings. The reliability of the zonal code SYLVIA, which is used to support safety assessments in nuclear facilities, has then been analysed from these experimental results. © 2012 Elsevier Ltd.


Boulenouar M.,University of Science and Technology of Oran | Meslem A.,LEPTIAB | Imine B.,University of Science and Technology of Oran | Nastase I.,Technical University of Civil Engineering Bucharest
Mechanika | Year: 2011

Numerical simulations of turbulent free jet issuing from a six-lobed diffuser, using the shear stress transport k-ω model have been carried out. The three-dimensional calculations have been done on a tetrahedral mesh with 1.7 million cells. The numerical predictions have been compared with PIV measurements. This comparison shows reasonable agreement, principally, in terms of centreline longitudinal velocity, volumetric flow rate, longitudinal mean fluctuating velocity and streamwise vorticity. With these results, the shear stress transport k-ω model can be considered for future studies as an efficient mean for quickly optimizing lobed diffuser design and analyzing exit Reynolds number effect on the mixing performance of this three-dimensional flow for HVAC application.


Minard A.,LEPTIAB | Goujard B.,LEPTIAB | Sakout A.,LEPTIAB | Billon A.,University of Liège | Embrechts J.-J.,University of Liège
Proceedings of Forum Acusticum | Year: 2011

This study aims at defining reliable acoustic cues for the measure, characterization and prediction of the acoustic comfort of air-treatment systems (ATS). To meet customers' expectations, industrial products tend increasingly to follow a process of "sound design". In this process, the perceptual evaluation of sound quality is a necessary step to defene acoustic specifications. Nonetheless, the possible influence of factors related to room acoustics is often neglected. Contextual parameters, such as room acoustics' factors, should be integrated in the evaluation of sound quality in order to defene acoustic comfort as it is perceived in a real environment. First, a sound corpus of a reasonable size was constituted through a categorization experiment over a large recording database of different types of ATS. Then, an experiment was conducted to build a scale of acoustic comfort over the sound corpus and relevant acoustic features for prediction were identified. Two different situations were considered: diotic presentation and auralized presentation (using a 3D vector base amplitude panning system), the results of which were finally compared in order to address the relative importance of room acoustics' factors for the judgement of the acoustic comfort of ATS.


Razafindralandy D.,LEPTIAB | Hamdouni A.,LEPTIAB | Al Sayed N.,LEPTIAB | Al Sayed N.,Électricité de France
Physica A: Statistical Mechanics and its Applications | Year: 2012

The symmetry group of the non-isothermal Navier-Stokes equations is used to develop physics-preserving turbulence models for the subgrid stress tensor and the subgrid heat flux. The Reynolds analogy is not used. The theoretical properties of the models are investigated. In particular, their compatibility with the scaling laws of the flow is proven. A numerical test, in the configuration of an air flow in a ventilated and differentially heated room is presented. © 2012 Elsevier B.V. All rights reserved.


Dumon A.,LEPTIAB | Allery C.,LEPTIAB | Ammar A.,Arts et Metiers ParisTech
European Journal of Computational Mechanics | Year: 2010

In this work, the Proper Generalized Decomposition (PGD) method will be considered in order to solve Navier-stokes equations with a stream-vorticity formulation by looking for the solution as a sum of tensor product functions. In the first stage, PGD will be applied to a model equation in order to test the capacity of the method to treat some timedependent problem. Then, we will solve the Navier-Stokes problem in the case of the liddriven cavity for different Reynolds numbers (Re = 100, 1000 and 10000). Finally, the PGD method will be compared to the standard resolution technique, both in terms of CPU time and accuracy. © 2010 Lavoisier, Paris.


Dumon A.,LEPTIAB | Allery C.,LEPTIAB | Ammar A.,Arts et Metiers ParisTech
Journal of Computational Physics | Year: 2011

In this work, the PGD method will be considered for solving some problems of fluid mechanics by looking for the solution as a sum of tensor product functions. In the first stage, the equations of Stokes and Burgers will be solved. Then, we will solve the Navier-Stokes problem in the case of the lid-driven cavity for different Reynolds numbers (Re= 100, 1000 and 10,000). Finally, the PGD method will be compared to the standard resolution technique, both in terms of CPU time and accuracy. © 2010 Elsevier Inc.

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