The influence of uniform momentum zones on frictional drag within the turbulent boundary layer

2020 ◽  
Author(s):  
Kangjun Wang ◽  
Nan Jiang
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Frictional Drag

Influence of a large-eddy breakup device on the frictional drag in a turbulent boundary layer

2017 ◽  
Vol 29 (6) ◽  
pp. 065103 ◽  
Author(s):  
Joon-Seok Kim ◽  
Jinyul Hwang ◽  
Min Yoon ◽  
Junsun Ahn ◽  
Hyung Jin Sung
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Frictional Drag ◽  
Large Eddy

The Energetics of Hovering in the Mandarin Fish (Synchropus Picturatus)

1979 ◽  
Vol 82 (1) ◽  
pp. 25-33 ◽  
Author(s):  
R. W. BLAKE
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Ground Effect ◽  
Water Velocity ◽  
Total Power ◽  
Mandarin Fish ◽  
Pectoral Fin ◽  
Frictional Drag ◽  
Hovering Flight ◽  
Negatively Buoyant

The influence of the ground effect on the energetics of hovering in Synchropus picturatus Peters, a negatively buoyant, demersal teleost was studied. Changes in pectoral fin kinematics, the ultimate water velocity in the wake below the fins, the calculated minimum induced thrust and power required to hover are related to the height at which the animal hovers above the substrate. The profile power required to overcome the frictional drag on the fins has been calculated for the case of both a laminar and a turbulent boundary layer over the fins. Reductions in the total power needed to hover (as compared with that required out of ground effect) of 30–60% have been calculated for Synchropus when hovering at commonly observed heights above the bottom. Results are discussed in relation to the hovering flight of birds, insects and helicopters.

An Experiment on Flat Plate Turbulent Boundary Layer Flow—The Effect of Local Fluid Addition on Friction and Velocity Distribution

1958 ◽  
Vol 62 (566) ◽  
pp. 135-138
Author(s):  
Henry Barrow
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Flow ◽  
Flat Surface ◽  
Frictional Drag ◽  
Flow Through ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow ◽  
Image Position ◽  
Uniform Stream

For a Flat Surface at zero incidence in a deep uniform stream, the total frictional drag F per unit width of the surface can be calculated from the well known equationUsing the momentum principle in the usual way, it can be shown that when fluid is added locally to the flow through the surface, the total frictional drag F1 is given by

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