Anatomy of a laminar starting thermal plume at high Prandtl number
- 543 Downloads
We present an experimental study of the dynamics of a plume generated from a small heat source in a high Prandtl number fluid with a strongly temperature-dependent viscosity. The velocity field was determined with particle image velocimetry, while the temperature field was measured using differential interferometry and thermochromic liquid crystals. The combination of these different techniques run simultaneously allows us to identify the different stages of plume development, and to compare the positions of key-features of the velocity field (centers of rotation, maximum vorticity locations, stagnation points) respective to the plume thermal anomaly, for Prandtl numbers greater than 103. We further show that the thermal structure of the plume stem is well predicted by the constant viscosity model of Batchelor (Q J R Met Soc 80: 339–358, 1954) for viscosity ratios up to 50.
KeywordsParticle Image Velocimetry Viscosity Ratio Thermal Plume High Prandtl Number Plume Dynamic
This work has benefited from discussions with Neil Ribe, Eric Mittelsteadt, Peter van Keken, and Béatrice Guerrier. It was funded by program DyETI of INSU/CNRS, the French ANR “BEGDY” and the collaboration between IPGP in Paris and ERI in Tokyo. The manuscript has been improved, thanks to the constructive comments of two anonymous reviewers.
Movie 1: RUN1. On the left side of the screen is the left half of the plume seen by differential interferometry, and on the right side is the other half of the plume followed by the thermochromic liquid crystals isotherms. The total duration of the movie is 600 s (1782 KB)
- Davaille A, Limare A (2007) Laboratory studies on mantle convection. In: Bercovici D, Schubert G (eds) Treatise of geophysics. Elsevier, Amsterdam, pp 89–165Google Scholar
- Davaille A, Androvandi S, Vatteville J, Limare A, Vidal V, Lebars M (2008) Thermal boundary layer instabilities in viscous fluids. In: ISFV13—13th International symposium on flow visualization, July 1–4, 2008, Nice, France, p 12, available at http://www.ipgp.fr/~limare/317.pdf
- Happel J, Brenner H (1973) Low Reynolds number hydrodynamics. Noordhoff, LeydenGoogle Scholar
- Kumagai I, Davaille A, Kurita K (2007) On the fate of thermal plumes at density interface, earth planet. Sci Lett 254: 180–193Google Scholar
- Kumagai I, Davaille A, Kurita K, Stutzmann E (2008) Mantle plumes: thin, fat, successful, or failing? Constraints to explain hot spot volcanism through time and space, Geophys. Res Lett 35: L16301 http://www.dx.doi.org/10.1029/2008GL035079
- Limare A, Kumagai I, Vatteville J, Davaille A (2008) Thermal plumes visualisation: differential interferometry versus thermochromic liquid crystals, ISFV13—13th international symposium on flow visualization, July 1–4, 2008, Nice, France, p 12, available at http://www.ipgp.fr/~limare/318.pdf
- Morton BR, Taylor GI, Turner JS (1956) Turbulent gravitational convection from maintained and instantaneous sources. Proc R Soc Lond A 234:1–23Google Scholar