Mixing Characteristics in a Conical Taylor-Couette Flow System at Low Reynolds Numbers

AbstractWe numerically simulate turbulent Taylor–Couette flow for independently rotating inner and outer cylinders, focusing on the analogy with turbulent Rayleigh–Bénard flow. Reynolds numbers of $R{e}_{i} = 8\times 1{0}^{3} $ and $R{e}_{o} = \pm 4\times 1{0}^{3} $ of the inner and outer cylinders, respectively, are reached, corresponding to Taylor numbers $Ta$ up to $1{0}^{8} $. Effective scaling laws for the torque and other system responses are found. Recent experiments with the Twente Turbulent Taylor–Couette (${T}^{3} C$) setup and with a similar facility in Maryland at very high Reynolds numbers have revealed an optimum transport at a certain non-zero rotation rate ratio $a= - {\omega }_{o} / {\omega }_{i} $ of about ${a}_{\mathit{opt}} = 0. 33$. For large enough $Ta$ in the numerically accessible range we also find such an optimum transport at non-zero counter-rotation. The position of this maximum is found to shift with the driving, reaching a maximum of ${a}_{\mathit{opt}} = 0. 15$ for $Ta= 2. 5\times 1{0}^{7} $. An explanation for this shift is elucidated, consistent with the experimental result that ${a}_{\mathit{opt}} $ becomes approximately independent of the driving strength for large enough Reynolds numbers. We furthermore numerically calculate the angular velocity profiles and visualize the different flow structures for the various regimes. By writing the equations in a frame co-rotating with the outer cylinder a link is found between the local angular velocity profiles and the global transport quantities.

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Heat Transfer Enhancement in Axial Taylor-Couette Flow

Heat Transfer: Volume 1 ◽

10.1115/ht2005-72746 ◽

2005 ◽

Cited By ~ 5

Author(s):

S. Gilchrist ◽

C. Y. Ching ◽

D. Ewing

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Nusselt Number ◽

Couette Flow ◽

Reynolds Numbers ◽

Taylor Number ◽

Number Range ◽

Taylor Couette ◽

Number Case ◽

Taylor Couette Flow

An experimental investigation was performed to determine the effect that surface roughness has on the heat transfer in an axial Taylor-Couette flow. The experiments were performed using an inner rotating cylinder in a stationary water jacket for Taylor numbers of 106 to 5×107 and axial Reynolds numbers of 900 to 2100. Experiments were performed for a smooth inner cylinder, a cylinder with two-dimensional rib roughness and a cylinder with three-dimensional cubic protrusions. The heat transfer results for the smooth cylinder were in good agreement with existing experimental data. The change in the Nusselt number was relatively independent of the axial Reynolds number for the cylinder with rib roughness. This result was similar to the smooth wall case but the heat transfer was enhanced by 5% to 40% over the Taylor number range. The Nusselt number for the cylinder with cubic protrusions exhibited an axial Reynolds number dependence. For a low axial Reynolds number of 980, the Nusselt number increased with the Taylor number in a similar way to the other test cylinders. At higher axial Reynolds numbers, the heat transfer was initially independent of the Taylor number before increasing with Taylor number similar to the lower Reynolds number case. In this higher axial Reynolds number case the heat transfer was enhanced by up to 100% at the lowest Taylor number of 1×106 and by approximately 35% at the highest Taylor number of 5×107.

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Turbulent Taylor–Couette Flow at Large Reynolds Numbers*

Journal of Engineering Physics and Thermophysics ◽

10.1007/s10891-016-1488-3 ◽

2016 ◽

Vol 89 (5) ◽

pp. 1247-1254

Author(s):

V. A. Babkin

Keyword(s):

Couette Flow ◽

Reynolds Numbers ◽

Taylor Couette ◽

Taylor Couette Flow

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An investigation of turbulent plane Couette flow at low Reynolds numbers

Journal of Fluid Mechanics ◽

10.1017/s0022112095000747 ◽

1995 ◽

Vol 286 ◽

pp. 291-325 ◽

Cited By ~ 123

Author(s):

Knut H. Bech ◽

Nils Tillmark ◽

P. Henrik Alfredsson ◽

Helge I. Andersson

Keyword(s):

Couette Flow ◽

Reynolds Stress ◽

Reynolds Numbers ◽

Wall Turbulence ◽

Turbulence Structure ◽

Plane Couette Flow ◽

Mean Flow ◽

Low Reynolds Numbers ◽

Low Reynolds ◽

Near Wall

The turbulent structure in plane Couette flow at low Reynolds numbers is studied using data obtained both from numerical simulation and physical experiments. It is shown that the near-wall turbulence structure is quite similar to what has earlier been found in plane Poiseuille flow; however, there are also some large differences especially regarding Reynolds stress production. The commonly held view that the maximum in Reynolds stress close to the wall in Poiseuille and boundary layer flows is due to the turbulence-generating events must be modified as plane Couette flow does not exhibit such a maximum, although the near-wall coherent structures are quite similar. For two-dimensional mean flow, turbulence production occurs only for the streamwise fluctuations, and the present study shows the importance of the pressure—strain redistribution in connection with the near-wall coherent events.

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