Intermittent heat instabilities in an air plume
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Published:2016-08-30
Issue:4
Volume:23
Page:319-330
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ISSN:1607-7946
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Container-title:Nonlinear Processes in Geophysics
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language:en
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Short-container-title:Nonlin. Processes Geophys.
Author:
Le Mouël Jean-Louis, Kossobokov Vladimir G.ORCID, Perrier Frederic, Morat Pierre
Abstract
Abstract. We report the results of heating experiments carried out in an abandoned limestone quarry close to Paris, in an isolated room of a volume of about 400 m3. A heat source made of a metallic resistor of power 100 W was installed on the floor of the room, at distance from the walls. High-quality temperature sensors, with a response time of 20 s, were fixed on a 2 m long bar. In a series of 24 h heating experiments the bar had been set up horizontally at different heights or vertically along the axis of the plume to record changes in temperature distribution with a sampling time varying from 20 to 120 s. When taken in averages over 24 h, the temperatures present the classical shape of steady-state plumes, as described by classical models. On the contrary, the temperature time series show a rich dynamic plume flow with intermittent trains of oscillations, spatially coherent, of large amplitude and a period around 400 s, separated by intervals of relative quiescence whose duration can reach several hours. To our knowledge, no specific theory is available to explain this behavior, which appears to be a chaotic interaction between a turbulent plume and a stratified environment. The observed behavior, with first-order factorization of a smooth spatial function with a global temporal intermittent function, could be a universal feature of some turbulent plumes in geophysical environments.
Publisher
Copernicus GmbH
Reference33 articles.
1. Blanter, E. M., Le Mouël, J.-L., Perrier, F., and Shnirman, M.: Short-term correlation of solar activity and sunspot: Evidence of lifetime increase, Sol. Phys., 237, 329–350, 2006. 2. Carazzo, G., Girault, F., Aubry, T., Bouquerel, H., and Kaminski, E.: Laboratory experiments of forced plumes in a density-stratified crossflow and implications for volcanic plumes, Geophys. Res. Lett., 41, 8759–8766, 2014. 3. Carazzo, G., Kaminski, E., and Tait, S.: The route to self-similarity in turbulent jets and plumes, J. Fluid Mech., 547, 137–148, 2006. 4. Crouzeix, C., Le Mouël, J.-L., Perrier, F., Richon, P., and Morat, P.: Long-term thermal evolution and effect of low power heating in an underground quarry, C. R. Geosci., 335, 345–354, 2003. 5. Crouzeix, C., Le Mouël, J.-L., Perrier, F., Shnirman, M. G., and Blanter E.: Long-term persistence of the spatial organization of temperature fluctuation lifetime in turbulent air avalanches, Phys. Rev. E, 74, 036308, https://doi.org/10.1103/PhysRevE.74.036308, 2006a.
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