THE TURBULENT BOUNDARY LAYER AND FRICTIONAL DRAG CHARACTERISTICS OF NEW GENERATION MARINE FOULING CONTROL COATINGS

Turbulent boundary-layer measurements have been carried out on flat surfaces coated with two different new generation marine antifoulings. The coatings were applied on 1-m-long test sections that were fitted in a 2.1-m-long flat plate setup. The measurements were carried out in two different recirculating water tunnels by means of two-component laser Doppler velocimetry and were compared with measurements of a smooth steel reference surface and a surface covered with sand grit. Both coatings exhibited an increase in frictional resistance compared to the reference surface, but the increase was significantly smaller for the Foul(ing) Release coatings than for the Tin-free SPC coating. The coatings did not significantly affect the boundary-layer thickness. When expressed in inner variables, the coatings did not have an effect on the turbulence intensity profiles, but when expressed in outer variables, the coatings affected the near-wall turbulence intensities.

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A rapid benchtop method to assess biofilm on marine fouling control coatings

Biofouling ◽

10.1080/08927014.2021.1929937 ◽

2021 ◽

pp. 1-13

Author(s):

Simon P. J. Dennington ◽

Alexandra Jackson ◽

Alistair A. Finnie ◽

Julian A. Wharton ◽

Jennifer E. Longyear ◽

...

Keyword(s):

Marine Fouling ◽

Fouling Control ◽

Fouling Control Coatings

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

Journal of Experimental Biology ◽

10.1242/jeb.82.1.25 ◽

1979 ◽

Vol 82 (1) ◽

pp. 25-33 ◽

Cited By ~ 1

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.

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

Journal of the Royal Aeronautical Society ◽

10.1017/s0368393100068176 ◽

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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