Search

International audience; In the Sub-Saharan African countries like Djibouti, the energy situation, the high rate of urban areas growth and the inadequate techniques of construction offer an exciting potential for the bioclimatic approach and sustainable construction. However, this poorly explored potential requires an investigation of different construction types in Djibouti and a good knowledge of the behavior of buildings components. Further a low energy building can be obtained because of the good realization of all its components. In fact, roofs call for attention as they represent a large part of a building's total surface area and amount of absorbed solar radiation. The goal of this paper is to investigate the benefit of using double skin-ventilated roofs for reducing cooling load under the Djiboutian climate. It is a first step towards ideas that will transform local construction practices to make them effective in energy, economic and functional dimensions. During investigation, we compared a ventilated roof assembly with traditional configuration after that the consistency of our model was validated with experiment of the literature findings. The computational fluid dynamics (CFD) model has been used for the characterization of the airflow and heat transfer phenomena in the ventilation cavity and provide fundamental information about the thermal performance of the roof. The results show the amount of the energy saving obtainable by the double-skin ventilated roof.

International audience; In this paper the sound source identification problem is addressed with the use of the lattice Boltzmann method. To this aim, a time-reversed problem coupled to a complex differentiation method is used. In order to circumvent the inherent instability of the time-reversed lattice Boltzmann scheme, a method based on a split of the lattice Boltzmann equation into a mean and a perturbation component is used. Lattice Boltzmann method formulation around an arbitrary base flow is recalled and specific applications to acoustics are presented. The implementation of the noise source detection method for two-dimensional weakly compressible (low Mach number) flows is discussed, and the applicability of the method is demonstrated.

In order to solve structural problems submitted to a fluid-induced loading, we are interested in solving a fluid-structure interaction problem involving a deforming solid and a viscous fluid, under incompressible flow. We propose to use a partitioned but strongly coupled Gauss-Seidel scheme. We propose to solve the fluid part of the simulation by a finite element method with a scalable mixed domain decomposition strategy. A fictitious domain method enables taking into account the fluid-structure interface inside each fluid subdomain. Here, we describe the domain decomposition method and the coupling process on a stationary problem.