Du Puits, Ronald; Willert, Christian E.:
The evolution of the boundary layer in turbulent Rayleigh-Bénard convection in air
In: Physics of fluids : devoted to the publication of original theoretical, computational, and experimental contributions to the dynamics of gases, liquids, and complex or multiphase fluids, Vol. 28, No. 4, 15 Seiten, Article 044108
2016Journal article
Technische Universität Ilmenau (1992-) » Department of Mechanical Engineering (1992-) » Institute of Thermodynamics and Fluid Dynamics (1992-) » Endowed Professorship Aerodynamics (2013-)
Title:
The evolution of the boundary layer in turbulent Rayleigh-Bénard convection in air
Author:
Du Puits, RonaldTU
GND
133937690
ORCID
0000-0002-5749-3817ORCID iD
SCOPUS
14821876800
Other
connected with university
;Willert, Christian E.
GND
118024655
ORCID
0000-0002-1668-0181ORCID iD
Year of publication:
2016
DOI
10.1063/1.4947261
PPN:
858616343
Language of text:
English
Appears in
Physics of fluids : devoted to the publication of original theoretical, computational, and experimental contributions to the dynamics of gases, liquids, and complex or multiphase fluids
in:
Vol. 28, No. 4, 15 Seiten, Article 044108
PPN:
268757771
ZDB ID
1472743-2
Keyword, Topic:
ilm <2016> ; Stiftungsprofessur Aerodynamik <Ilmenau> ; Verfasser ; Zeitschriftenaufsatz ; referiert
Media:
online resources
Type of resource:
Text
Peer Reviewed:
Yes
Part of statistic:
Yes
DESTATIS Subject Classification:
6900 Maschinenbau allgemein

Abstract in English:

We report measurements of the near-wall flow field in turbulent Rayleigh-Bénard convection in air (Pr = 0.7) using particle imagevelocimetry. The measurements were performed in a thin, rectangular sample at fixed Rayleigh number Ra = 1.45 × 10^10. In particular, we focus on the evolution of the boundary layer that a single convection roll generates along its path at the lower horizontal plate. We identify three specific flow regions along this path: (i) a region of wall-normal impingement of the down flow close to one corner of the sample, (ii) a region where a shear layer with almost constant thickness evolves, and (iii) a region in which this boundary layer grows and eventually detaches from the plate surface at the opposite corner of the sample. Our measurements with a spatial resolution better than 1/500 of the total thickness of the boundary layer show that the typical velocity field as well as its statistics qualitatively varies between the three flow regions. In particular, it could be verified that the shear layer region covering about 75% of the total area of the plate is in transition to turbulence at the Rayleigh number as low as investigated in the present work.