Turbulent drag reduction characteristics induced by calf-thymus DNA

2005 ◽  
Vol 350 (1) ◽  
pp. 84-88 ◽  
Author(s):  
S.T. Lim ◽  
S.J. Park ◽  
C.K. Chan ◽  
H.J. Choi
Keyword(s):  
Drag Reduction ◽  
Calf Thymus Dna ◽  
Turbulent Drag Reduction ◽  
Turbulent Drag ◽  
Calf Thymus ◽  
Reduction Characteristics

Turbulent drag reduction characteristics of amylopectin and its derivative

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Sung Taek Lim ◽  
Hyoung Jin Choi ◽  
Diptirani Biswal ◽  
Ram Prakash Singh
Keyword(s):  
Drag Reduction ◽  
Polymer Concentration ◽  
Rotating Disk ◽  
Turbulent Drag Reduction ◽  
Experimental Conditions ◽  
Shear Stability ◽  
Turbulent Drag ◽  
Strong Shear ◽  
Shaft Torque ◽  
Reduction Characteristics

Abstract Using amylopectin (AP) and a derivative, we systematically investigated their turbulent drag reduction characteristics and shear stability. The expected shear stability of polysaccharides as drag reducing and flocculating agents triggered our study on structural modification of AP. For this purpose, we prepared a derivative of AP, viz. AP grafted with polyacrylamide (GA), in which the granular form of AP powder (≈10 μm) changed into a mixture of larger fibrils and lumps. Using a rotating-disk apparatus, we measured the shaft torque and calculated the turbulent drag reduction (DR) efficiency under various experimental conditions, i.e., different polymer concentration, rotation speed, and temperature. Contrary to AP, GA showed relatively high DR efficiencies (27%) and very strong shear resistance.

scholarly journals Analysis of anisotropically permeable surfaces for turbulent drag reduction

2017 ◽  
Vol 2 (11) ◽  
Author(s):  
Nabil Abderrahaman-Elena ◽  
Ricardo García-Mayoral
Keyword(s):  
Drag Reduction ◽  
Turbulent Drag Reduction ◽  
Turbulent Drag

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.

Sign in / Sign up

Export Citation Format

Share Document