An experimental study of high Rayleigh number natural convection in a horizontal annulus
- Univ. of Texas, Austin, TX (United States). Dept. of Mechanical Engineering
Experiments have been performed to obtain detailed measurements of the flow field and mean temperature distribution in a differentially heated horizontal annulus for air (Pr = 0.703) for 1.0 {times} 10{sup 6} < Ra{sub L} < 1.0 {times} 10{sup 8}. A two-component laser Doppler velocimeter is used to acquire time-resolved radial and azimuthal velocity measurements in the annulus, which are used to obtain power spectral density (PSD) estimates of the velocity fluctuations in the buoyant plume arising above the heated inner cylinder. The PSD provides information on the dynamical behavior of the flow within the plume and the turbulence scales produced by the buoyant flow. Probability density functions (PDF) are also determined from the velocity measurements, providing additional information about the instabilities associated with the plume. Flow visualization is also used to reveal information about the development of oscillatory flow regimes and the onset of turbulence as Ra{sub L} increases. In addition, axially averaged temperature distributions in the plume region are obtained by holographic interferometry. These measurements provide quantitative information regarding the thermal field in the plume region, including the extent of the plume and its effect on the flow. The results are consistent with the results of previous studies and give further insight into the onset and development of turbulence in natural convection flows.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States)
- OSTI ID:
- 445504
- Report Number(s):
- CONF-950828--; ISBN 0-7918-1709-1
- Country of Publication:
- United States
- Language:
- English
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