Investigation of thermal convection in water columns using particle image velocimetry

Particle image velocity measurements were applied on thermally driven convection at low Rayleigh numbers. In a model experiment using a water column heated from bottom and cooled from above, the velocity field was studied at different vertical temperature gradients. In the testing facility with high...

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Veröffentlicht in:	Experiments in fluids 2012-06, Vol.52 (6), p.1465-1474
Hauptverfasser:	Berthold, S., Resagk, C.
Format:	Artikel
Sprache:	eng
Schlagworte:	Boreholes Circulation Convection Convection and heat transfer Engineering Engineering Fluid Dynamics Engineering Thermodynamics Exact sciences and technology Fluid dynamics Fluid flow Fluid- and Aerodynamics Fundamental areas of phenomenology (including applications) Heat and Mass Transfer Instrumentation for fluid dynamics Particle image velocimetry Physics Research Article Temperature gradient Turbulent flows, convection, and heat transfer Water circulation
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Zusammenfassung:	Particle image velocity measurements were applied on thermally driven convection at low Rayleigh numbers. In a model experiment using a water column heated from bottom and cooled from above, the velocity field was studied at different vertical temperature gradients. In the testing facility with high aspect ratio (about 19) representing a 1-m-long column with 5 cm diameter, occurrence of free convection was verified for destabilizing temperature gradients of 0.1–2 K/m. The PIV results revealed that significant flow exists already at low vertical temperature gradients. The velocity of the stable large-scale circulations increased linearly with temperature gradient (
ISSN:	0723-4864 1432-1114
DOI:	10.1007/s00348-012-1267-7