Closure to “Discussions of ‘Drag Reduction by Ejecting Additive Solutions Into Pure-Water Boundary Layer’” (1972, ASME J. Basic Eng., 94, p. 755)

1972 ◽  
Vol 94 (4) ◽  
pp. 756-756 ◽  
Author(s):  
Jin Wu ◽  
M. P. Tulin
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Pure Water

Drag Reduction by Ejecting Additive Solutions Into Pure-Water Boundary Layer

1972 ◽  
Vol 94 (4) ◽  
pp. 749-754 ◽  
Author(s):  
Jin Wu ◽  
M. P. Tulin
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Flat Plate ◽  
Pure Water ◽  
Plane Boundary ◽  
External Flows ◽  
Additive Solution

Drag reduction caused by ejecting additive solutions from a slot into a pure-water boundary layer on a flat plate has been systematically studied. Results include drag measurements for a plane boundary, smooth and rough, with various openings of the slot and with various concentrations and discharges of the ejected additive solution. Conclusions have been drawn on the additive requirement in external flows and on the ejection technique for an optimum drag reduction.

Turbulence Structure Modification and Drag Reduction by Microbubble Injections in a Boundary Layer Channel Flow

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
C. C. Gutiérrez-Torres ◽  
Y. A. Hassan ◽  
J. A. Jimenez-Bernal
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Channel Flow ◽  
Single Phase ◽  
Pure Water ◽  
Channel Height ◽  
Turbulence Structure ◽  
Two Phase ◽  
Flow Measurements ◽  
Phase Water

Turbulent boundary layer modification in a channel flow using injection of microbubbles as a means to achieve drag reduction was studied. The physical mechanism of this phenomenon is not yet fully understood. To obtain some information related to this phenomenon, single-phase (pure water) flow and two-phase (water and microbubbles) channel flow measurements are taken. The void fraction conditions were varied while maintaining a Reynolds number of 5128 based on the half channel height. The study indicates that the presence of microbubbles within the boundary layer modifies the turbulence structure such that variations in time and space turbulent scales are observed, as well as ejection and sweep phenomena.

Turbulent Boundary-Layer Drag Reduction

2003 ◽  
Author(s):  
Paul Dimotakis ◽  
Patrick Diamond ◽  
Freeman Dyson ◽  
David Hammer ◽  
Jonathan Katz
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Drag Reduction
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