EFFECT OF VORTEX CELL STRUCTURE ON BIFURCATION PROPERTIES IN A TAYLORVORTEX FLOW SYSTEM

Bifurcation phenomena in a finite-length Taylor-Couette flow system ha ve been observed by an electrochemical technique. The axial wavelength was varied as the characteristic parameter of vortex cell structure b y varying the aspect ratio of the annular flow space and controlling t he inner cylinder acceleration up to a steady rotation speed. Multi-re solution analysis in wavelets was used not only for noise reduction, b ut also for extraction of low frequency components from the experiment al time-series data. When the dimensionless axial wavelength lambda/d < 1, the first fundamental frequency f(1)/f(r) of singly periodic wavy vortex flow was fixed at a unique value independent of the magnitude of lambda/d. When lambda/d greater than or equal to 1, on the other ha nd, f(1) was not fixed uniquely but showed some variation, depending o n the magnitude of lambda/d. In the transition to doubly periodic wavy vortex flow, not only Hopf bifurcation but also two-cycle period doub ling bifurcation occurred in some cases when lambda/d < 1, The first a nd second fundamental frequencies, f(1) and f(2) have tendencies to in crease with increasing lambda/d in spite of some exceptions. In the pr ocess of a transition to weakly turbulent wavy vortex flow, two-torus motion in phase space broke up at all wavelengths without frequency lo cking.