Prediction of drag reduction effect by streamwise traveling wave-like wall deformation in turbulent channel flow at practically high Reynolds numbers

2020 ◽  
Vol 82 ◽  
pp. 108550
Author(s):  
Yusuke Nabae ◽  
Ken Kawai ◽  
Koji Fukagata
Keyword(s):  
Drag Reduction ◽  
Channel Flow ◽  
Traveling Wave ◽  
Turbulent Channel Flow ◽  
Reynolds Numbers ◽  
High Reynolds Numbers ◽  
Wall Deformation ◽  
Reduction Effect ◽  
High Reynolds

Diffusion of a Tangential Drag-Reducing Polymer Injection on a Flat Plate at High Reynolds Numbers

1976 ◽  
Vol 20 (03) ◽  
pp. 171-180 ◽  
Author(s):  
Daniel H. Fruman ◽  
Marshall P Tulin
Keyword(s):  
Drag Reduction ◽  
Flat Plate ◽  
Concentration Distribution ◽  
Reynolds Numbers ◽  
Polymer Injection ◽  
High Reynolds Numbers ◽  
Pure Solvent ◽  
Reduction Effect ◽  
High Reynolds ◽  
Drag Reducing Polymer

The diffusion of a thin tangential jet of an aqueous solution of drag-reducing polymer injected into the water-turbulent boundary layer of a flat plate at a freestream Reynolds number, 3.6 × 107, and the accompanying drag reduction are investigated for a variety of initial concentrations and ratios of injection to freestream velocities. The concentration distribution along the wall is found to be mainly represented by two regions. In the first region the wall concentration is practically constant and equal to the injected one; in the second region the concentration varies approximately as the inverse of the distance from the injection slit. The length of the first region is significantly increased by the polymer solution injection as compared with the pure solvent injection. The drag-reduction effect associated with the polymer injection depends on the trailing-edge concentration achieved as a result of the diffusion process.

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