Rayleigh-Benard convection in limited domains. Part 1: Oscillatory flow
- Univ. di Roma La Sapienza, Rome (Italy). Dipt. di Meccanica e Aeronautica
- CIRA, Capua (Italy)
For the past century, Rayleigh-Benard convection has been the subject of very intensive theoretical, experimental, and numerical studies. Analysis of the Rayleigh-Benard problem is of practical importance for many engineering applications (e.g., thermal comfort, crystal growth, solar collectors). Here, transition from the steady state to an oscillatory regime in three-dimensional limited aspect ratio boxes, filled with an incompressible fluid and heated from below, has been examined by direct numerical simulation. Two different physical problems have been considered: the first is related to a domain 3.5 [times] 1 [times] 2.1 filled with water at 70 C (Prandtl number 2.5); the second considers a domain 2.4 [times] 1 [times] 1.2 filled with water at 33 C (Prandtl number 5). The Rayleigh number has been varied from 20,000 to 80,000. A new procedure based on a statistical approach for evaluation of the critical Rayleigh number for transition from steady state to oscillatory flow (Ra[sub II]) has been introduced in order to reduce numerical errors and estimate the error bars. A systematic study for the determination of Ra[sub II] has been conducted as a function of the geometries considered and the different flow structures observed.
- OSTI ID:
- 6383016
- Journal Information:
- Numerical Heat Transfer. Part A, Applications, Journal Name: Numerical Heat Transfer. Part A, Applications Vol. 36:1; ISSN 1040-7782; ISSN NHAAES
- Country of Publication:
- United States
- Language:
- English
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