Transition from hexagons to rolls in convection in fluids under non-Boussinesq conditions
Anno: 1992
Autori: Pampaloni E., Perez Garcia C., Albavetti L., Ciliberto S.
Affiliazione autori: Departamento de Fisica, Universidad de Navarrra, Pamplona, Spain;
Istituto Nazionale di Ottica, Largo E. Fermi 6, 50125 Firenze, Italy
Abstract: The transition between hexagons and rolls in convective patterns has been studied. The transition thresholds and changes in the Nusselt number are discussed theoretically in terms of calculations made by Busse (1967 a) and with amplitude equations. Experiments have been done in a shallow layer of pure water under non-Boussinesq conditions using complementary techniques: shadowgraph (qualitative), optical (based on the deflections of a laser beam) and calorimetric. The experimental values of the critical Rayleigh number R(c) and the critical wavenumber k(c) are in agreement with theoretical ones. However, theory and experiments show some discrepancies in the slopes of the non-dimensional convective heat flow curve and in the thresholds of the hysteretic hexagons rolls transition. These discrepancies are discussed in terms of lateral effects and of the presence of defects in the pattern.
Giornale/Rivista: JOURNAL OF FLUID MECHANICS
Volume: 234 Da Pagina: 393 A: 416
Parole chiavi: RAYLEIGH-BENARD CONVECTION; WAVE-NUMBER SELECTION; HEAT-TRANSPORT; AMPLITUDE EQUATION; SPATIAL VARIATIONDOI: 10.1017/S0022112092000831Citazioni: 28dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-04-28Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui