Browsing by Author "Henry, Daniel"

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    Laminar-turbulent transition regimes in the conical Taylor-Couette flow system
    (EDP Sciences, 2017) Yahi, Fatma; Bouabdallah, Ahcene; Hamnoune, Yasmina; Botton, Valéry; Henry, Daniel; Millet, Séverine; Rousset, François; Adachi, Takahiro
    The present work is intended to experimentally study the Taylor-Couette flow between coaxial cones. The inner cone is rotated and the outer cone is maintained fixed. Both cones have the same apex angle Φ =12°, giving a constant annular gap δ =0.12. The height of the fluid column is H=155 mm. The working fluid is assumed as Newtonian and has constant properties (as density and viscosity) within the range of the required experimental conditions. By means of visualization techniques, the critical thresholds related to the onset of various instabilities have been obtained and the corresponding flow modes have been identified. Using images processing, spatio-temporal diagrams have also been calculated, showing the characteristics (wavelength, drift velocity) of the downward helical motion. The results obtained for these transition regimes are compared to those of Wimmer et al. [1-3]
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    Three-dimensional effect of high frequency vibration on convection in silicon melt
    (American Physical Society, 2020) Mokhtari, Faiza; Kaddeche, Slim; Henry, Daniel; Bouarab, Samia; Medelfef, Abdessamed; Botton, Valéry
    Using the Chebyshev spectral method, the effect of high frequency (HF) vibrations on a cubic cell heated from the side and containing a liquid metal is investigated. This study extends the numerical and theoretical two-dimensional results presented in the authors’ past work [Phys. Fluids 31, 043605 (2019)] about the influence of HF vibration direction on the flow structure in a rectangular crucible filled with a liquid metal. The vibration direction can now be three dimensional, and not limited to the main flow plane. In practice, the study considers that the vibration vector is contained in one of the three principal planes of the cavity (xz,xy, and yz planes). Two different cases, i.e., under weightlessness and gravity conditions, are considered for each type of vibration to better understand the separate effect of both vibration and buoyancy forces and also their combined effects. Each type of vibration has its own features and affects the flow intensity and patterns differently