Influence of rheological parameters in all drag reduction regimes of turbulent channel flow with polymer additives

2008 ◽  
Vol 15 (S1) ◽  
pp. 275-279
Author(s):  
Chang-feng Li ◽  
Zuo-guang Zhao ◽  
Gui-fen Wu ◽  
Xiao-dong Feng
Keyword(s):  
Drag Reduction ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Rheological Parameters ◽  
Polymer Additives

Direct Numerical Simulations of Turbulent Channel Flow With Polymer Additives

2020 ◽  
Vol 36 (5) ◽  
pp. 691-698
Author(s):  
Che-Yu Lin ◽  
Chao-An Lin
Keyword(s):  
Drag Reduction ◽  
Numerical Simulations ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Weissenberg Number ◽  
Direct Numerical Simulations ◽  
Polymer Additives ◽  
Boundary Treatments ◽  
Conformation Tensor ◽  
Nonlinear Elastic

ABSTRACTDirect numerical simulations have been applied to simulate flows with polymer additives. FENE-P (finite-extensible-nonlinear-elastic-Peterlin) dumbbell model solving for the conformation tensor is adopted to investigate the influence of the polymer on the flowfield. Boundary treatments of the conformation tensor on the flowfield are examined first, where boundary condition based on the linear extrapolation scheme provides more accurate results with second-order accurate error norms. Further simulations of the turbulent channel flow at different Weissenberg numbers are also conducted to investigate the influence on drag reduction. Drag reduction increases in tandem with the increase of Weissenberg number and the increase saturates at Weτ~200, where the drag reduction is close to the maximum drag reduction (MDR) limit. At the regime of y+ > 5, the viscous layer thickens with the increase of the Weissenberg number showing a departure from the traditional log-law profile, and the velocity profiles approach the MDR line at high Weissenberg number. The Reynolds stress decreases in tandem with the increase of Weτ, whereas the levels of laminar stress and polymer stress act adversely. However, as the Weissenberg number increases, the proportion of the laminar stress in the total stress increases, and this contributes to the drag reduction of the polymer flow.

Drag reduction by polymer additives in a turbulent channel flow

2003 ◽  
Vol 486 ◽  
pp. 213-238 ◽  
Author(s):  
TAEGEE MIN ◽  
JUNG YUL YOO ◽  
HAECHEON CHOI ◽  
DANIEL D. JOSEPH
Keyword(s):  
Drag Reduction ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Polymer Additives

Maximum drag reduction in a turbulent channel flow by polymer additives

2003 ◽  
Vol 492 ◽  
pp. 91-100 ◽  
Author(s):  
TAEGEE MIN ◽  
HAECHEON CHOI ◽  
JUNG YUL YOO
Keyword(s):  
Drag Reduction ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Polymer Additives ◽  
Maximum Drag Reduction

DRAG REDUCTION IN TURBULENT CHANNEL FLOW WITH TWO-TIERED SUPERHYDROPHOBIC WALLS

2017 ◽  
Author(s):  
Richard Perkins ◽  
Julie Crockett ◽  
Daniel Maynes
Keyword(s):  
Drag Reduction ◽  
Channel Flow ◽  
Turbulent Channel Flow

scholarly journals Turbulent channel flow over an anisotropic porous wall – drag increase and reduction

2018 ◽  
Vol 842 ◽  
pp. 381-394 ◽  
Author(s):  
Marco E. Rosti ◽  
Luca Brandt ◽  
Alfredo Pinelli
Keyword(s):  
Drag Reduction ◽  
Channel Flow ◽  
High Speed ◽  
Vertical Direction ◽  
Porous Wall ◽  
Turbulent Channel Flow ◽  
Spanwise Direction ◽  
Normal Velocity ◽  
Porous Walls ◽  
The One

The effect of the variations of the permeability tensor on the close-to-the-wall behaviour of a turbulent channel flow bounded by porous walls is explored using a set of direct numerical simulations. It is found that the total drag can be either reduced or increased by more than 20 % by adjusting the permeability directional properties. Drag reduction is achieved for the case of materials with permeability in the vertical direction lower than the one in the wall-parallel planes. This configuration limits the wall-normal velocity at the interface while promoting an increase of the tangential slip velocity leading to an almost ‘one-component’ turbulence where the low- and high-speed streak coherence is strongly enhanced. On the other hand, strong drag increase is found when high wall-normal and low wall-parallel permeabilities are prescribed. In this condition, the enhancement of the wall-normal fluctuations due to the reduced wall-blocking effect triggers the onset of structures which are strongly correlated in the spanwise direction, a phenomenon observed by other authors in flows over isotropic porous layers or over ribletted walls with large protrusion heights. The use of anisotropic porous walls for drag reduction is particularly attractive since equal gains can be achieved at different Reynolds numbers by rescaling the magnitude of the permeability only.

Application of compact neural network for drag reduction in a turbulent channel flow at low Reynolds numbers

2008 ◽  
Vol 20 (4) ◽  
pp. 045104 ◽  
Author(s):  
Li Vodinh Lorang ◽  
Bérengère Podvin ◽  
Patrick Le Quéré
Keyword(s):  
Neural Network ◽  
Drag Reduction ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Low Reynolds
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