scholarly journals Relationship between vortex structure and drag reduction in Bubbly Taylor-Couette flow

2008 ◽  
Vol 28-1 (2) ◽  
pp. 1013-1013
Author(s):  
Koji YOSHIDA ◽  
Yuji TASAKA ◽  
Yuichi MURAI ◽  
Yasushi TAKEDA
Keyword(s):  
Drag Reduction ◽  
Couette Flow ◽  
Vortex Structure ◽  
Taylor Couette ◽  
Taylor Couette Flow

Drag reduction with polymer addition in Taylor-Couette flow with Taylor instabilities

2017 ◽  
Author(s):  
Edson Soares ◽  
Renato Siqueira ◽  
Rafhael Andrade ◽  
Ivanor Martins da Silva
Keyword(s):  
Drag Reduction ◽  
Couette Flow ◽  
Polymer Addition ◽  
Taylor Couette ◽  
Taylor Couette Flow

scholarly journals Microbubbly drag reduction in Taylor–Couette flow in the wavy vortex regime

2008 ◽  
Vol 608 ◽  
pp. 21-41 ◽  
Author(s):  
KAZUYASU SUGIYAMA ◽  
ENRICO CALZAVARINI ◽  
DETLEF LOHSE
Keyword(s):  
Reynolds Number ◽  
Drag Reduction ◽  
Couette Flow ◽  
Physical Mechanism ◽  
Dilute Suspensions ◽  
Fluid Coupling ◽  
Taylor Couette ◽  
The Individual ◽  
Reynolds Number Dependence ◽  
Taylor Couette Flow

We investigate the effect of microbubbles on Taylor–Couette flow by means of direct numerical simulations. We employ an Eulerian–Lagrangian approach with a gas–fluid coupling based on the point-force approximation. Added mass, drag, lift and gravity are taken into account in the modelling of the motion of the individual bubble. We find that very dilute suspensions of small non-deformable bubbles (volume void fraction below 1%, zero Weber number and bubble Reynolds number ≲10) induce a robust statistically steady drag reduction (up to 20%) in the wavy vortex flow regime (Re=600–2500). The Reynolds number dependence of the normalized torque (the so-called torque reduction ratio (TRR) which corresponds to the drag reduction) is consistent with a recent series of experimental measurements performed by Murai et al. (J. Phys. Conf. Ser. vol. 14, 2005, p. 143). Our analysis suggests that the physical mechanism for the torque reduction in this regime is due to the local axial forcing, induced by rising bubbles, that is able to break the highly dissipative Taylor wavy vortices in the system. We finally show that the lift force acting on the bubble is crucial in this process. When it is neglected, the bubbles preferentially accumulate near the inner cylinder and the bulk flow is less efficiently modified. Movies are available with the online version of the paper.

Structural Drag Reduction in Taylor-Couette Flow

2013 ◽  
Vol 300-301 ◽  
pp. 285-289
Author(s):  
Ya Bo Xue ◽  
Zhen Qiang Yao ◽  
Cang Xue Li
Keyword(s):  
Drag Reduction ◽  
Couette Flow ◽  
Structural Design ◽  
Simple Structure ◽  
Flow System ◽  
Speed Ratio ◽  
Taylor Couette ◽  
Low Efficiency ◽  
Canned Motor ◽  
Taylor Couette Flow

Energy consumption of fluid machinery, especially for canned motor pump that rotates in water, increases sharply as radius or speed increases. It not only leads to low efficiency of the pump, but also probably suppresses heat transfer between stator winding and water. According to researches on Taylor-Couette flow, dimensionless torque decreases obviously when both cylinders rotate in certain speed ratio. It inspires us to propose a structural design to realizing drag reduction in Taylor-Couette flow system, which has simple structure but huge potential.

Bubbly drag reduction in turbulent Taylor-Couette flow

2007 ◽  
pp. 416-417
Author(s):  
Detlef Lohse ◽  
Thomas H. van den Berg ◽  
Dennis P. M. van Gils ◽  
Daniel P. Lathrop
Keyword(s):  
Drag Reduction ◽  
Couette Flow ◽  
Taylor Couette ◽  
Taylor Couette Flow

scholarly journals Microbubble Drag Reduction Mechanism Observed in Taylor-Couette Flow

2007 ◽  
Vol 27 (Supplement1) ◽  
pp. 129-130
Author(s):  
Yuichi MURAI ◽  
Hiroshi OIWA ◽  
Yasushi TAKEDA
Keyword(s):  
Drag Reduction ◽  
Couette Flow ◽  
Reduction Mechanism ◽  
Taylor Couette ◽  
Taylor Couette Flow
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