scholarly journals Turbulent drag reduction at moderate Reynolds numbers via spanwise velocity waves

PAMM ◽  
2012 ◽  
Vol 12 (1) ◽  
pp. 563-564 ◽  
Author(s):  
Davide Gatti ◽  
Maurizio Quadrio
Keyword(s):  
Drag Reduction ◽  
Reynolds Numbers ◽  
Turbulent Drag Reduction ◽  
Turbulent Drag ◽  
Spanwise Velocity

Drag Reduction by Culture Solutions of Dry Malted Rice

2009 ◽  
Author(s):  
Keizo Watanabe ◽  
Satoshi Ogata
Keyword(s):  
Drag Reduction ◽  
Pipe Flow ◽  
Reynolds Numbers ◽  
Type B ◽  
Turbulent Drag Reduction ◽  
Turbulent Drag ◽  
Diameter Pipe ◽  
Maximum Drag Reduction ◽  
Inner Diameter ◽  
Biopolymer Solutions

Turbulent drag reduction by culture solutions of dry malted rice was investigated in a 2.00mm-inner-diameter pipe flow of length 50 diameters at Reynolds numbers from 500 to 8000. The drag reducing abilities of the solutions were tested by comparing drag reduction effectiveness at different concentrations and culture times in water. Comparisons between polysaccharide biopolymer solutions and culture solutions of dry malted rice revealed that the test solutions exhibited Type B drag reduction, which were roughly parallel to, but displaced upwards from, the Newtonian Prandtl-Ka´rma´n law. The maximum drag reduction ration was about 30% at a Reynolds number of 8,000. It is shown also that the onset point of drag reduction phenomena was Ref = 200.

scholarly journals Streamwise oscillation of spanwise velocity at the wall of a channel for turbulent drag reduction

2009 ◽  
Vol 21 (11) ◽  
pp. 115109 ◽  
Author(s):  
Claudio Viotti ◽  
Maurizio Quadrio ◽  
Paolo Luchini
Keyword(s):  
Drag Reduction ◽  
Turbulent Drag Reduction ◽  
Turbulent Drag ◽  
Spanwise Velocity

scholarly journals Fibre-induced drag reduction

2008 ◽  
Vol 602 ◽  
pp. 209-218 ◽  
Author(s):  
J. J. J. GILLISSEN ◽  
B. J. BOERSMA ◽  
P. H. MORTENSEN ◽  
H. I. ANDERSSON
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Drag Reduction ◽  
Elastic Layer ◽  
Turbulent Drag Reduction ◽  
Rigid Polymer ◽  
Fibre Concentration ◽  
Induced Drag ◽  
Turbulent Drag

We use direct numerical simulation to study turbulent drag reduction by rigid polymer additives, referred to as fibres. The simulations agree with experimental data from the literature in terms of friction factor dependence on Reynolds number and fibre concentration. An expression for drag reduction is derived by adopting the concept of the elastic layer.

scholarly journals Turbulent drag reduction in a dilute polymeric solution flowing through a fiber-implanted circular pipe.

1988 ◽  
Vol 21 (4) ◽  
pp. 441-443
Author(s):  
HIROTSUGU HATTORI ◽  
TOMOO YAMAUCHI ◽  
SEIICHI TANABE ◽  
HIDEOMI MATSUDA
Keyword(s):  
Drag Reduction ◽  
Circular Pipe ◽  
Turbulent Drag Reduction ◽  
Polymeric Solution ◽  
Turbulent Drag
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