Visualization and spectrum of turbulent transition in thermal plume - Exact determination of flow state by spectrum
Abstract
The aim is to carefully visualize a thermal plume, to exactly determine a flow state by the criterion of gradient on the power spectrum density (PSD), and to clarify a turbulent transition in a thermal plume. A thermal plume occurred from a horizontal line heat source in a large enclosure filled with a stable thermally stratified fluid. The thermal plume was carefully visualized. A time-dependent temperature of the thermal plume was measured on the midplane, on the several heights and to the axial direction of the wire. The PSD was obtained from time series data of the plume temperature. A flow state can be quantitatively and exactly determined in the thermal plume by the criterion of PSD gradient. Finally, a turbulent transition and an entrainment phenomena were investigated and clarified in the thermal plume.
- Publication:
-
Flow Visualization V; Proceedings of the 5th International Symposium
- Pub Date:
- 1990
- Bibcode:
- 1990flvi.proc..743N
- Keywords:
-
- Boundary Layer Transition;
- Flow Visualization;
- Plumes;
- Power Spectra;
- Turbulent Flow;
- Entrainment;
- Flow Distribution;
- Heat Sources;
- Spectrum Analysis;
- Stratified Flow;
- Time Temperature Parameter;
- Fluid Mechanics and Heat Transfer