Simultaneous temperature and velocity Lagrangian measurements in turbulent thermal convection - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Fluid Mechanics Année : 2016

Simultaneous temperature and velocity Lagrangian measurements in turbulent thermal convection

Résumé

We report joint Lagrangian velocity and temperature measurements in turbulent thermal convection. Measurements are performed using an improved version (extended autonomy) of the neutrally-buoyant instrumented particle [Shew et al., 2007] that was used by Gasteuil et al. [2007] to performed experiments in a parallelepipedic Rayleigh-Bénard cell. The temperature signal is obtained from a RF-transmitter. Simultaneously, we determine particle's position and velocity with one camera, which grants access to the Lagrangian heat flux. Due to the extended autonomy of the present particle, we obtain well converged temperature and velocity statistics, as well as pseudo-eulerian maps of velocity and heat flux. Present experimental results have also been compared with the results obtained by a corresponding campaign of Direct Numerical Simulations and Lagrangian Tracking of massless tracers. The comparison between experimental and numerical results shows the accuracy and reliability of our experimental measurements and points also out the finite-size effects of the particle. Finally, the analysis of Lagrangian velocity and temperature frequency spectra is shown and discussed. In particular, we observe that temperature spectra exhibit an anomalous f −2.5 frequency scaling, likely representing the ubiquitous passive and active scalar behavior of temperature.
Fichier principal
Vignette du fichier
JFM_Liot_version_HAL.pdf (2.26 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01506810 , version 1 (12-04-2017)

Licence

Copyright (Tous droits réservés)

Identifiants

Citer

Olivier Liot, Fanny Seychelles, Francesco Zonta, Sergio Chibbaro, Thibaut Coudarchet, et al.. Simultaneous temperature and velocity Lagrangian measurements in turbulent thermal convection. Journal of Fluid Mechanics, 2016, 794, pp.655-675. ⟨10.1017/jfm.2016.190⟩. ⟨hal-01506810⟩
93 Consultations
91 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More