Taylor-Couette flow control using the outer cylinder cross-section variation strategy

A numerical study of a controlled flow evolving in a Taylor-Couette system is presented in this paper. The study is devoted to investigate the effect of the outer cylinder cross-section variation on the flow behavior. It is aimed to make assessment of the flow response in terms of the criticality of the early transitional flow regimes and the accompanying flow topology alterations. The numerical simulations are carried out on the Fluent software package for a three-dimensional incompressible flow. The basic system is characterized by a height H  = 200 mm, a ratio of the inner to the outer cylinders radii η  = 0.9, an aspect ratio corresponding to the cylinders height reported to the gap length Г  = 40 and a ratio of the gap to the radius of the inner cylinder δ  = 0.1. The numerical deformation of the outer cylinder is executed using the dynamic mesh program according to a predefined function implemented in a homemade program as an UDF (user defined function). It is established that the first instability mode of transition is retarded from Ta c1  = 41.33, corresponding to the first Taylor number critical value, to Ta c1  = 70 when the deforming amplitude is equal to 15% the external cylinder diameter value. This flow relaminarization process is accompanied by substantial modifications in the flow behavior and configuration.