Onset of thermal ripples at the interface of an evaporating liquid under a flow of inert gas
- 235 Downloads
The dynamics of thermal ripples at the interface of a volatile pure liquid (C2H5OH) is studied experimentally and numerically. Liquid evaporates under a flow of inert gas (N2) circulating along the interface. The evaporation rate is varied by regulating both the gas flow rate and the gas pressure. Experiments in microgravity environment allowed to identify a transition to “interfacial turbulence,” along which some particular events such as nearly periodic and possible intermittent behaviors. Direct numerical simulations have been performed, and compare qualitatively well with experimental results, offering new insights into the physical mechanisms involved. Small-scale ripples appear to arise from a secondary instability of large-scale convection cells and their motion seems to follow the corresponding large-scale surface flow. The relative role of surface tension and buoyancy in triggering these flows is assessed by comparing experiments and simulations in both microgravity and ground conditions. Qualitative features compare satisfactorily well such as typical speed and orientation of the thermal ripples, as well as spiral flow in the bulk.
KeywordsRayleigh Number Direct Numerical Simulation Evaporation Rate Marangoni Number Secondary Instability
We would like to thank the referees for their valuable suggestions. We heartfully thank the whole ESA sounding rocket staff and the whole ITEL 2 team at the Swedish Space Corporation for their invaluable work during the experiment development and flight. We are also grateful to Christophe Minetti and Jean-Charles Dupin for their help in preparing some figures. We wish to acknowledge the support of E.S.A. (European Space Agency) and of BELSPO (Belgian Federal Science Policy Office) through the CIMEX (Convective Interfacial Mass Exchange) Research Program. B.S. and P.C. gratefully acknowledge financial support of the “Fonds de la Recherche Scientifique—FNRS”.
- Colinet P, Joannes L, Iorio C, Kabov O, Dupont O, Gorza S-P, Legros J (2001) In: Proceedings of the 15th ESA symposium on European rocket & balloon programmes and related research (Biarritz, Spain), vol ESA SP-471, pp 423–427Google Scholar
- Janson O, Broxvall M, Löth K, Anderson P, Houltz Y, Colinet P, Scheid B, Joannes L, Saul B, Haesendonck B, et al. (2005) In: Proceedings of the 17th ESA symposium on European rocket & balloon programmes and related research, 30 May–2 June, Sandefjord, Norway. Full text can be found on http://homepages.ulb.ac.be/∼bscheid/Jan05.pdf
- Joannes L, Dupont O, Dubois F, Colinet P, Legros J (2000) In: Proceedings of the 9th international symposium on flow vizualization (Edinburgh), p 428, cD-ROM Proceedings (ISBN 0-9533991-1-7)Google Scholar
- Joannes L, Dupont O, Gorza S, Colinet P, Legros J, Lanen T, Oksuzoglu H (2001) In: Proceedings of Fringe 2001, 4th international workshop on automatic processing of fringe patterns, pp 506–513Google Scholar
- Löth K, Larsson B, Schneider H, Janson O, Houltz Y, Colinet P, Iorio C, Joannes L, Dupont O (2002) In: Proceedings of the 53rd international astronautical congress, 10–19 October, Houston, Texas (The World Space Congress)Google Scholar
- Molenkamp T (1998) Ph.D. thesis, University of GroningenGoogle Scholar