Components of wall shear rate in wavy Taylor–Couette flow

Kristiawan, Magdalena; Jirout, Tomáš; Sobolı́k, V.

doi:10.1016/j.expthermflusci.2011.04.018

Cited by 6 publications

(11 citation statements)

References 46 publications

(61 reference statements)

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“…As it approaches the flow separation region, a sudden decrease of ̅̅̅̅ is observed in a region denoted as the drop. This drop could be attributed to the emergence of a pair of secondary vortices in the flow separation region as reported in Akonur & Lueptow (2003) and Kristiawan, Jirout & Sobolík (2011). ̅̅̅̅ exhibits a similar drop for other Re in the flow separation region of ATVF (see Figure 17 and Figure 18).…”

Section: Spatial Behaviour Of Vl In Atvf (Axisymmetric Flow Structure)supporting

confidence: 73%

“…However, in the TCF problems, Taylor vortices are confined between two walls that lead to the appearance of both jet impingement and flow separation at the near-wall regions of same junction ( i.e., inflow or outflow regions) of two counter-rotating vortices (Dumont et al, 2002 ;Akonur & Lueptow, 2003;Sobolik et. al., 2011;Kristiawan, Jirout & Sobolík, 2011). A study of the near-wall regions in the TCF may be the key for a fuller and better understanding of the underlying flow physics.…”

Section: Introductionmentioning

confidence: 99%

“…above findings show several salient flow features of wide gap problems in TCF with four wavelengths fluid column, namely the appearance of strong periodic secondary flow, comparatively weaker Taylor vortices, sudden increase in the NNW and occurrence of the azimuthal wave during the transition of ATVF into WVF flow regime. The influence of these flow features on the reduction of normalized torque in the transition flow regime is another significant observation in this investigation.Past studies of narrow gap problems show that near-wall regions of inflow and outflow regions play a crucial role in the eventual outcomes of TCF(Akonur & Lueptow, 2003;Kristiawan, Jirout & Sobolík, 2011;Sobolik et al, 2011). Along the same line of investigation as small gap problems, we take a closer look at the dynamics of the near-wall region of both the inner and the outer walls with the aids of the analysis of the viscous layer (VL) thickness.…”

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confidence: 99%

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Numerical study on wide gap Taylor Couette flow with flow transition

2019

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This study aims to investigate the possible sources of non-axisymmetric disturbances and their propagation mechanism in Taylor Couette flow (TCF) for wide gap problems using direct numerical simulation with a radius ratio of 0.5 and Reynolds number (Re) ranging from 60 to 650. Here, attention is focused on the viscous layer (VL) thickness in near-wall regions and its spatial distribution along the axial direction to gain an insight into the origin and propagation of non-axisymmetric disturbances. The results show that an axisymmetric Taylor-vortex flow occurs when Re is between 68 and 425. Above Re = 425, transition from axisymmetric to non-axisymmetric flow is observed up to Re = 575 before the emergence of wavy-vortex flow. From the variation of VL thickness with Re, the VL does not experience any significant changes in the flow separation region of the inner wall, as well as jet impingement region of both the inner and outer walls. However, a sudden increase in VL thickness in the flow separation region of the outer wall reveals possible source of non-axisymmetric disturbances in the flow separation region of the outer wall. These disturbances develop into the periodic secondary flow as the axisymmetric flow transforms into non-axisymmetric flow and this leads to the emergence of azimuthal wave. The periodic secondary flow contributes to sudden increase in the natural wavelength and rapid reduction in the strength of two counter-rotating Taylor vortices. This in turn leads to a substantial reduction of torque in the transition flow vis-a-vis axisymmetric Taylor-vortex flow.

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Section: Spatial Behaviour Of Vl In Atvf (Axisymmetric Flow Structure)supporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Numerical study on wide gap Taylor Couette flow with flow transition

2019

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“…Compared to a batch reactor, the Couette-Taylor vortex can intensify the agitation and induce uniform fluidic motion, implying that the mass transfer of the reactant is uniform and enhanced (Campero and Vigil, 1997;Kataoka et al, 1995;Zhu et al, 2010). In addition, a high wall shear stress can be obtained, which is expected to improve the dispersion of particles in the solution (Fellay and Vanni, 2012;Kristiawan et al, 2011;Pomchaitaward et al, 2003). The agitation and shear stress usually increase with a higher Taylor number in a Couette-Taylor vortex system (Watanabe et al, 2006).…”

Section: Introductionmentioning

confidence: 96%

Preparation of black pigment with the Couette–Taylor vortex for electrophoretic displays

Kim¹,

Park²,

Lee³

et al. 2014

Chemical Engineering Science

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“…Kim measured the pressure losses of different working fluids in TCP flow and drew the conclusion that the increase in flow disturbance caused by the Taylor vortex resulted in an increase in the skin friction coefficient, but he did not provide an in-depth explanation [6][7][8]. Kristiawan investigated the components of the wall shear rate via experiments and found that the axial distributions of the wall shear rate components averaged over the perimeter were similar to the distribution in steady Taylor vortices [9]. However, Kristiawan's tests were performed in slow axial flow, which cannot be introduced in the turbulent state.…”

Section: Introductionmentioning

confidence: 99%

Flow Resistance Modeling for Coolant Distribution within Canned Motor Cooling Loops

Wang

Yao

Shen

2020

Chin. J. Mech. Eng.

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Taylor-Couette-Poiseuille (TCP) flow dominates the inner water-cooling circulation of canned motor reactor coolant pumps. Current research on TCP flow focuses on torque behaviors and flow regime transitions through experiments and simulations. However, research on axial flow resistance in a large Reynolds number turbulent state is not sufficient, especially for the various flow patterns. This study is devoted to investigating the influence of annular flow on the axial flow resistance of liquid in the coaxial cylinders of the stator and rotor in canned motor reactor coolant pumps, and predicting the coolant flow distribution between the upper coil cooling loop and lower bearing lubricating loop for safe operation. The axial flow resistance, coupled with the annular rotation, is experimentally investigated at a flow rate with an axial Reynolds number, Re a , from 2.6 × 10 3 to 6.0 × 10 3 and rotational Reynolds number, Re t , from 1.6 × 10 4 to 4.0 × 10 4. It is revealed that the axial flow frictional coefficient varies against the axial flow rate in linear relation sets with logarithmic coordinates, which shift up when the flow has a higher Re t. Further examination of the axial flow resistance, with the Re a extending to 3.5 × 10 5 and Re t up to 1.6 × 10 5 , by simulation shows gentle variation rates in the axial flow frictional coefficients against the Re a. The relation curves with different Re t values converge when the Re a exceeds 3.5 × 10 5. A prediction model for TCP flow consisting of a polygonal approximation with logarithmic coordinates is developed to estimate the axial flow resistance against different axial and rotational Reynolds numbers for the evaluation of heat and mass transfer during transition states and the engineering design of the canned motor chamber structure.

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Components of wall shear rate in wavy Taylor–Couette flow

Cited by 6 publications

References 46 publications

Numerical study on wide gap Taylor Couette flow with flow transition

Numerical study on wide gap Taylor Couette flow with flow transition

Preparation of black pigment with the Couette–Taylor vortex for electrophoretic displays

Flow Resistance Modeling for Coolant Distribution within Canned Motor Cooling Loops

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