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Mechanism of vortices appearance in the Taylor-Couette flow system
Author(s): Messaoud KHIRENNAS, H. Oualli, mekadem mahmoud, AZZAM Tarik, Ahmed BENAICHE, Ahcen bouabdallah
Keywords: CFD, Taylor-Couette flow, CFD, Ekman cells, Fluent software, TVF, WVF.
This paper concerns 3D CFD simulations of Taylor-Couette flow using Ansys Fluent software package. The basic system geometry is characterized by the height H= 150mm, ratio of inner to outer cylinder radii η= 0.9, radial gap δ= 0.11 and an aspect ratio corresponding to the cylinder height reported to the gap length Г= H/δ = 15. For the natural flow evolution (no actuation applied), it is attempted to follow the early flow genesis stages since Ekman cells onset first symptoms at very low Taylor number (Ta=10-4) to the first (TVF) and second (WVF) instability settlement at Tac1= 43.8 and Tac2= 54 respectively. It is sought to elucidate the underlying mechanism responsible for this flow type genesis and to identify all the intermediate embryonic stages up to complete vortices birth leading to the entire annular space occupation. The obtained results show that the presence of Ekman structures is already detected for a Taylor number as low as Ta= 10-4 in terms of localized pressure zones on the system endwalls surfaces regularly distributed according to a π/2 phase lag. These pressure zones azimuthally propagate to meet and cover the entire gap circumference at Ta~10-2 to10-1.

Journal of Applied Fluid Mechanics

The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating.

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