Control of thermocapillary instabilities far from threshold
2005 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 17, no 10Article in journal (Refereed) Published
We report experiments on control of thermocapillary instabilities at high temperature differences, in an annular geometry. Previous studies [Phys. Fluids 14, 3039 (2002)] showed that a reasonable control of oscillatory instability could be achieved by optimizing a local heating feedback process. We conducted experiments with a basic flow converging from periphery to center. This constitutes a more unstable configuration than previously, and enables appearance of higher-order instabilities and chaos. Applying successfully local feedback control to the periodic state close to the threshold, we extend the process to higher temperature differences, where nonlinear as well as proportional/derivative control laws are necessary to obtain a significant decrease of the temperature fluctuations. Finally, proportional control allows us to synchronize a chaotic state, to a periodic one.
Place, publisher, year, edition, pages
2005. Vol. 17, no 10
zone liquid bridge, cylindrical containers, benard convection, controlling chaos, feedback-control, active control, microgravity
IdentifiersURN: urn:nbn:se:kth:diva-15154DOI: 10.1063/1.2111144ISI: 000232939200048ScopusID: 2-s2.0-33645739111OAI: oai:DiVA.org:kth-15154DiVA: diva2:333195
QC 201005252010-08-052010-08-05Bibliographically approved