| Popis: |
It has been recognized since a long time that Rayleigh-Benard convection in binary mixtures possesses a rich variety of dynamical behaviors due to the coupling between the temperature and the concentration fields (since a more recent review does not exist, see e.g. Platten & Legros 1984). For example, the oscillatory onset of convection was not only theoretically predicted almost 20 years ago (Platten 1971 — Shteinberg 1971 — Hurle & Jakeman 1971 — Legros et al. 1972) but also experimentally observed by inserting temperature probes (thermocouple, thermistance, ...) inside the liquid layer (Platten & Chavepeyer 1973). In this last paper, far away from the critical point, very regular and sustained temperature oscillations were recorded in a circular container of large aspect ratio (diameter/height ≃ 13 cm/0.32 cm) were a regular roll pattern is even not expected. Also, an hysteretic effect in Schmidt—Milverton plots was discovered (Platten & Chavepeyer 1973). However the exact nature of the “oscillator” was not resolved. |
