Experimental and numerical shadowgraph in turbulent Rayleigh-Bénard convection with a rough boundary: investigation of plumes - Université Claude Bernard Lyon 1 Accéder directement au contenu
Pré-Publication, Document De Travail Année : 2020

Experimental and numerical shadowgraph in turbulent Rayleigh-Bénard convection with a rough boundary: investigation of plumes

Résumé

We show that, in the case of turbulent Rayleigh-Bénard convection, shadowgraph can be used to have quantitative results on the plumes statistics and their velocity. For this purpose, we compare the experimental shadowgraph of a Rayleigh-Bénard cell with the synthetic shadowgraph obtained by calculating the integrated 2D Laplacian of the temperature field from a numerical simulation very similar to the experiment. We use image processing tools to enhance the quality of the shadowgraph image, and obtain quantitative statistics for the thermal plumes, such as plume density, and plume velocity distribution. To highlight the efficiency of this new process of plume counting, we use, both in the experiment and in the numerical simulation, a turbulent Rayleigh-Bénard convection cell with a rough bottom surface, and a smooth top surface, where the statistics of the plumes can be influenced (or not) by the roughness. In addition, the distribution of velocity obtained from processing the synthetic shadowgraph images of the DNS or the experimental shadowgraph images, are compared to the velocity fluid at mid plane of the DNS or PIV measurement in the experiment, respectively. It will be shown that the mean velocity profile measured using the advection of the plumes is different from the average eulerian velocity profile.
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Dates et versions

hal-02329929 , version 1 (23-10-2019)
hal-02329929 , version 2 (29-02-2020)
hal-02329929 , version 3 (06-04-2020)

Identifiants

  • HAL Id : hal-02329929 , version 2

Citer

Berengere Podvin, Mebarek Belkadi, Laura Guislain, Anne Sergent, Bérengère Podvin, et al.. Experimental and numerical shadowgraph in turbulent Rayleigh-Bénard convection with a rough boundary: investigation of plumes. 2020. ⟨hal-02329929v2⟩
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