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

Abdelali, Ali; Oualli, H.; Rahmani, Abdallah Yacine; Merzkane, B.; Bouabdallah, A.

doi:10.1007/s40430-019-1758-z

Cited by 4 publications

(3 citation statements)

References 17 publications

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“…The first protocol is applied in order to better follow evolution of the flow until vortices disappearance. Abdelali et al (2019) used a technique to make the Taylor vortices disappear by combining the effect of the radial deformation of the inner cylinder with the oscillation of the free surface. The vortices disappear from the free surface in the depth direction.…”

Section: Effect Of the Axial Flow Field On The Taylor-couette Flowmentioning

confidence: 99%

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Axial Flow Effect on the Stability of Circular Couette Flow

Belkadi

Laghouati

Sobolı́k

et al. 2022

JAFM

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We investigate the effect of an axial Poiseuille annular flow on the stability of Taylor vortices via numerical simulation using CFD Ansys Fluent software. The working conditions are identical to those of the Taylor-Couette experimental device of the LaSIE laboratory, where the inner cylinder is rotated. An incompressible fluid of density ρ= 998 kg/m 3 , with a kinematic viscosity 𝜈 = 1.004 * 10 m 2 /s at a temperature T= 19.5 °C is considered. The geometrical parameters of the flow system are characterized by a height H=275 mm, a radius ratio η=0.804, and an axial aspect factor Γ=45.45. The axial Reynolds number and Taylor number are respectively in the ranges of 0 ≤ R ≤ 12 , and 0 ≤ 𝑇𝑎 ≤ 142.25. Flow control is carried out according to two distinct protocols to bring out the effect of axial flow on the evolution of the Taylor vortex Flow (TVF). The first consists of superimposing an azimuthal flow around the critical TVF threshold with increasing axial flow until the Taylor vortices disappear. In the second, an axial field is set and the Taylor number is varied until onset of the TVF mode. It is predicted that in the presence of an axial flow, the critical threshold for first instability triggering (TVF) is delayed. In addition, the ratio of the axial phase velocity to the mean axial velocity of the axial base flow is 1.16. This value agrees well with previous results reported in literature.

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Section: Effect Of the Axial Flow Field On The Taylor-couette Flowmentioning

confidence: 99%

“…The vortices disappear from the free surface in the depth direction. Abdelali et al (2019) by numerical and experimental study, concluded that the Taylor vortices can easily be destroyed using low deforming frequencies, but The Ekman cells requires a high frequency to be destroyed.…”

Section: Effect Of the Axial Flow Field On The Taylor-couette Flowmentioning

confidence: 99%

Axial Flow Effect on the Stability of Circular Couette Flow

Belkadi

Laghouati

Sobolı́k

et al. 2022

JAFM

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“…They found that this control strategy had a stabilizing effect on the evolving flow and the first flow bifurcation is delayed to a Taylor number Tac1 = 70 for a deforming amplitude of 15% the external cylinder diameter value. Abdelali et al (2019) investigated first instabilities onset delay using a controlling strategy based upon a combination of inner cylinder cross-section oscillation with a free surface effect. Two ranges of deformation frequencies are considered, lower frequencies, f < 3 Hz to destroy Taylor vortices, and higher frequencies, f > 20 Hz to make Ekman cells, identified as more resistant, completely disappearing.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Vortices Appearance in the Taylor-Couette Flow System

Khirennas

Oualli

Mekadem

et al. 2022

JAFM

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This work is devoted to study the Taylor-Couette flow at the early structuring stages. It is aimed to gain insight on the Taylor and Ekman vortices genesis mechanism since the first hints of presence detected at Ta=10 -4 . Simulations are carried out using Ansys Fluent software package. The basic system geometry is characterized bya height H= 150mm, ratio of inner to outer cylinder radii η= 0.9, radial gap δ= 0.11 and an aspect ratio corresponding to system height reported togap length, Г= H/δ = 15. Ekman and Taylor cells are tackled since the Taylor number Ta=10 -4 to the first (TVF) and second (WVF) instabilities settlement at Tac1= 43.8 and Tac2= 54, respectively. It is sought to shed light on the underlying mechanism responsible for flow genesis and to identify all the intermediate successive steps from ex-nihilo when the system is at rest up to complete vortices formation. The obtained results show that presence of Ekman cells is already perceptible since a Taylor number as low as Ta= 10 -4 . In fact, localized overpressure zones are detected on system inner endcaps surfaces regularly distributed according to a π/2 phase lag. These overpressure zones azimuthally propagate to meet and cover the entire gap circumference when Ta~10 -2 to10 -1 .

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