Turbulent drag reduction mechanism above a riblet surface

AIAA Journal ◽  
1994 ◽  
Vol 32 (9) ◽  
pp. 1781-1790 ◽  
Author(s):  
Yuji Suzuki ◽  
Nobuhide Kasagi
Keyword(s):  
Drag Reduction ◽  
Reduction Mechanism ◽  
Turbulent Drag Reduction ◽  
Turbulent Drag ◽  
Riblet Surface

scholarly journals Investigation of the Turbulent Drag Reduction Mechanism of a Kind of Microstructure on Riblet Surface

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Mingrui Ao ◽  
Miaocao Wang ◽  
Fulong Zhu
Keyword(s):  
Drag Reduction ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Water Area ◽  
Reduction Mechanism ◽  
Surface Drag ◽  
Groove Surface ◽  
Turbulent Drag ◽  
Micro Structures ◽  
Riblet Surface

With the k-ε renormalization group turbulence model, the drag reduction mechanism of three- dimensional spherical crown microstructure of different protruding heights distributing on the groove surface was studied in this paper. These spherical crown microstructures were divided into two categories according to the positive and negative of protruding height. The positive spherical crown micro-structures can destroy a large number of vortexes on the groove surface, which increases relative friction between water flow and the groove surface. With decreasing the vertical height of the spherical crown microstructure, the number of rupture vortexes gradually decreases. Due to the still water area causes by the blocking effect of the spherical crown microstructure, it was found that the shear stress on the groove surface can be reduced, which can form the entire drag reduction state. In another case, the spherical crown microstructures protrude in the negative direction, vortexes can be generated inside the spherical crown, it was found that these vortexes can effectively reduce the resistance in terms of pressure and friction. In a small volume, it was shown that the surface drag reduction rate of spherical crown microstructures protrudes in negative directions can be the same as high as 24.8%.

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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