کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
159397 | 457036 | 2005 | 13 صفحه PDF | دانلود رایگان |
The intermittent velocity fluctuations, induced by a change in the vertical location of the impeller, associated with the double- to single-loop transition in stirred vessels are thoroughly analyzed. It is shown that this type of flow-pattern instability is characterized by a multiscale and nested structure of the velocity fluctuations, in which intermittent bursts pertaining to the two regimes are intermingled in a seemingly “self-similar” way. A filtering procedure based on a Markovian approach grounded on the definition of a transfer probability matrix is proposed in order to deconvolute from the original time series the nested intermittent bursts corresponding to local single- and double-loop patterns. This technique permits to define and estimate macroscopic statistical properties, such as the average burst duration in one of the two-regimes, and the frequency that characterizes this type of flow pattern intermittency. A heuristic analysis of the dynamic origin of the flow-pattern transitions in terms of global bifurcations and attractor crisis is addressed.
Journal: Chemical Engineering Science - Volume 60, Issue 17, September 2005, Pages 4736–4748