Experiment and numerical simulation of Taylor-Couette flow controlled by oscillations of inner cylinder cross section

An experimental and numerical study of the controlled Taylor-Couette flow with free surface is presented in this work. It is aimed to carry out a controlling strategy based upon a combination of free surface effect and an inner cylinder cross section oscillation. Numerical simulations are performed using FLUENT software package for three-dimensional incompressible flows. The basic system geometry is characterized by a height H=170mm, an inner and outer cylinders with, respectively, R-1=31.5mm and R-2=35mm, a ratio of the inner to outer cylinder radii ?=0.9, an aspect ratio =28.5 and a ratio of the gap to the inner cylinder radius, =0.1. It is established that the first and the second instabilities are delayed. The Taylor vortices and Ekman cells can be destroyed throughout a process applicable for all the flow regimes encountered in the Taylor-Couette flow. The Taylor vortices show a particular sensitivity and can be easily destroyed using low deforming frequencies (f<3Hz). The Ekman cells, however, exhibit larger resistance to actuation and substantially higher deforming frequencies (f>20Hz) are required for the complete disappearance.