TIME-DEPENDENT PATTERNS IN COUNTERROTATING ECCENTRIC CYLINDERS

Nonlinear mode interactions and pattern formation occurring along the primary stability boundary for counterrotating eccentric cylinders hav e been studied experimentally. Counterrotating concentric cylinders pr oduce either Taylor vortex flow or spiral vortices with various azimut hal wave numbers. Eccentric cylinders break the rotational symmetry of the base flow, introducing a delay of the onset of the primary instab ility and changes in the locations of the bicritical points separating patterns with differing azimuthal wave number. A theoretical model fo r this system is in qualitative agreement with the observations.