Experimental method for investigating the formation of flow patterns in a very wide gap Taylor-Couette flow (?=0.1).

In this study, we investigate the turbulent Taylor-Couette (TC) flow experimentally. First, in order to show the formation of the different patterns in the flow, the flow was seeded with kalliroscope particles and by applying a vertical laser sheet we were able to capture the different patterns in the flow. For a further detailed study, the flow field was measured in horizontal planes at different cylinder heights using Particle image velocimetry (PIV). The formation of patterns appears for the counter-rotation configuration where the outer cylinder rotates in the opposing direction of the inner cylinder rotation. For low shear Reynolds numbers, stable Taylor vortices fulfilling the whole gap appear for very low counter-rotation rates. While for the same rotation rates and higher shear Reynold number, large scale patterns with shorter length scale compared to the classical Taylor vortices appears, which can be described as interlaced fingers from in and outflow. The existence of these patterns leads to enhanced angular momentum transport.