Highlights
— publicly accessible database of various turbulence statistics/budgets is set up.
— Two different turbulent solutions obtained for identical flow parameters are studied.
— Budgets of the Reynolds stress and turbulent heat flux components are assessed.
Abstract
Direct Numerical Simulations are performed to provide a fine description of the tu...
This study examines turbulent airflow and upward heat transport in real urban environments using a building-resolving large-eddy simulation model to understand the characteristics of turbulent airflow and upward heat transport when geometrical distributions of buildings are modified. The target areas were two real urban districts within Osaka City,...
We present a class of hyperbolic systems modeling two-phase, two-velocity flows that can be obtained from Hamilton's principle of stationary action, under conventional constraints: conservation of the mass for each component. The governing equations imply the conservation of total momentum and total energy. The hyperbolicity is guaranteed for small...
Studying non-linear optics systems is of practical importance because it applies to systems such as optical fibers and liquid crystals but also of theoretical importance because non-linear light exhibit properties very similar to hydrodynamics. Non-linear optics are modeled by an non-integrable equation which contains a rich physics. In this thesis...
Dans cette thèse, nous présentons une nouvelle technique expérimentale permettant la mesure spatio-temporelle du taux de dissipation à l'interface (paroi, surface libre, …) d'un écoulement. Cette technique, connue sous le nom anglais de Diffusing-Wave Spectroscopy (DWS), repose sur l'approximation de diffusion pour décrire la diffusion multiple de ...
Most theoretical studies of Rayleigh-Bénard Convection assume that the velocity boundary layer develops on the whole width or height H of the convection cell, or that the development length h scale with H . We argue that it is probably not the case, and examine the consequences of an intermediate asymptotics hypothesis in the sense of Barenblatt, t...
We report a wind tunnel study on the wake generated by a horizontal-axis (HAWT) and a vertical-axis wind turbine (VAWT). Two scaled models, one of each type, have been tested in a wind tunnel, under low blockage and at Reynolds numbers, based on the rotor diameter ?, of ReD = 265 x 103 for the HAWT and 330 x 103 for the VAWT. The models scale with ...
The atomization process is influenced by the deformation and breakup of droplets, which in turn affects the final distribution of droplet size. Several authors have related the breakup of droplets due to turbulence to their free oscillations and have shown that even, for low turbulence levels, droplets break due to a resonant mechanism. This phenom...
This work is part of a research project aimed at proposing numerical fluid simulations (CFD) capable of capturing the noise produced by rotating machines.The aim of this thesis is to study mesh adaptation methods for unsteady turbulent flows. We begin by describing the tools required for our studies, namely numerical methods, turbulence models and ...
Le stockage d'énergie est essentiel à la transition énergétique car il permet de découpler la production de l'énergie de sa consommation. Le stockage de chaleur thermocline en eau, utilisé dans les réseaux de chaleur à moyenne ou basse température, repose sur la stratification thermique dans une cuve. Les performances de ce type de stockage sont fo...
