The Measurement of the Drag Characteristics of Tin-free Self-polishing Co-polymers and Fouling Release Coatings Using a Rotor Apparatus

Candries, Maxim; Atlar, Mehmet; Ehsan, Mehdi; Pazouki, K

doi:10.1080/0892701021000026138

Cited by 38 publications

(36 citation statements)

References 12 publications

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“…Leer-Andersen and Larsson (2003) studied on a method for measuring the full-scale skin friction coefficient for biofouled and structured ship surfaces. Candries et al (2003) carried out an experimental study by rotor measurements that were coated with different marine coatings, Self-Polishing Co-polymer (SPC) and a Foul(ing) Release (FR) type. In a similar manner to that of the present study, the investigation of Candries and Atlar (2005) systematically compared the drag, boundary layer and roughness characteristics of marine surfaces coated with new generation antifouling paint systems involving commercially competitive SPC and FR coatings.…”

Section: Introductionmentioning

confidence: 99%

Turbulent boundary layer measurements over flat surfaces coated by nanostructured marine antifoulings

Ünal

Atlar

2012

Exp Fluids

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Whilst recent developments of nanotechnology are being exploited by chemists and marine biologists to understand how the completely environmentally friendly foul release coatings can control marine biofouling and how they can be developed further, the understanding of the hydrodynamic performances of these new generation coatings is being overlooked. This paper aims to investigate the relative boundary layer, roughness and drag characteristics of some novel nanostructured coatings, which were developed through a multi-European and multi-disciplined collaborative research project AMBIO (2010), within the framework of turbulent flows over rough surfaces. Zero-pressure-gradient, turbulent boundary layer flow measurements were conducted over flat surfaces coated with several newly developed nanostructured antifouling paints, along with some classic reference surfaces and a state-of-the-art commercial coating, in the Emerson Cavitation Tunnel (ECT) of Newcastle University. A large flat plane test bed that included interchangeable flat test sections was used for the experiments. The boundary layer data were collected with the aid of a two-dimensional DANTEC Laser Doppler Velocimetry (LDV) system. These measurements provided the main hydrodynamic properties of the newly developed nanostructured coatings including local skin friction coefficients, roughness functions and Reynolds stresses. The tests and subsequent analysis indicated the exceptionally good frictional properties of all coatings tested, in particular, the drag benefit of some new nanostructured coatings in the Reynolds number range investigated. The rapidly decreasing roughness function trends of AKZO19 and AKZO20 as the k þ s increases were remarkable along with the dissimilar roughness function character of all tested coatings to the well-known correlation curves warranting further research at higher Reynolds numbers. The wall similarity concept for the Reynolds stresses was only validated for the transitionally rough surfaces from ðy þ eÞ þ % 100 up to the end of the boundary layer.

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Section: Introductionmentioning

confidence: 99%

Turbulent boundary layer measurements over flat surfaces coated by nanostructured marine antifoulings

Ünal

Atlar

2012

Exp Fluids

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“…As application of biocidal antifouling (AF) paints is increasingly being restricted, fouling-release (FR) coatings are currently considered as alternative. Such non-toxic alternatives appear attractive, as they seem to reduce fuel consumption compared to conventional ablative AF coatings [3][4][5]. Bacteria are among the first microorganisms to colonize submersed interfaces to form biofilms [1].…”

Section: Introductionmentioning

confidence: 99%

Microfluidic Assay to Quantify the Adhesion of Marine Bacteria

2012

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For both, environmental and medical applications, the quantification of bacterial adhesion is of major importance to understand and support the development of new materials. For marine applications, the demand is driven by the quest for improved fouling-release coatings. To determine the attachment strength of bacteria to coatings, a microfluidic adhesion assay has been developed which allows probing at which critical wall shear stress bacteria are removed from the surface. Besides the experimental setup and the optimization of the assay, we measured adhesion of the marine bacterium Cobetia marina on a series of differently terminated self-assembled monolayers. The results showed that the adhesion strength of C. marina changes with surface chemistry. The difference in critical shear stress needed to remove bacteria can vary by more than one order of magnitude if a hydrophobic material is compared to an inert chemistry such as polyethylene glycol.

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“…Several other studies have specifically aimed to measure the baseline skin friction drag of antifouling and foul-release coatings in their un-fouled state (e.g. Candries et al [2003], Schultz [2004]). Beyond this, numerous studies have attempted to characterise the skin friction drag due to biofilms grown on a test plate inserted into specially designed water tunnels Schultz & Swain [1999], Walker et al [2013] or towed-plates Schultz [2004].…”

Section: Introductionmentioning

confidence: 99%

An assessment of the ship drag penalty arising from light calcareous tubeworm fouling

et al. 2016

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A test coupon coated with light calcareous tubeworm fouling was scanned, scaled and reproduced for wind-tunnel testing to determine the equivalent sand grain roughness ks. It was found that this surface had a ks = 0.325 mm, substantially less than previously reported values for light calcareous fouling. Any number of variations in surface topology could account for these different report values, such as sparseness, differences in species settlement etc. The experimental results were used to predict the drag on a fouled full scale ship. To achieve this, a modified method for predicting the total drag of a spatially developing turbulent boundary layer (TBL), such as that on the hull of a ship, is presented. The method numerically integrates the skin friction over the length of the boundary layer, assuming a widely accepted analytical form for the mean velocity profile of the TBL. The velocity profile contains the roughness (fouling) information, such that the prediction requires only an input of ks, free-stream velocity (ship speed), kinematic viscosity and the length of the boundary layer (hull length). Using the equivalent sandgrain roughness height determined from experiments, a FFG-7 Oliver Perry class Frigate is predicted to experience a 23% increase in total resistance at cruise, if its hull is coated in light calcareous tubeworm fouling. A similarly fouled Very Large Crude Carrier would experience a 34% increase in total resistance at cruise. turbulent boundary layer, skin friction drag, roughness, tubeworms

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The Measurement of the Drag Characteristics of Tin-free Self-polishing Co-polymers and Fouling Release Coatings Using a Rotor Apparatus

Cited by 38 publications

References 12 publications

Turbulent boundary layer measurements over flat surfaces coated by nanostructured marine antifoulings

Turbulent boundary layer measurements over flat surfaces coated by nanostructured marine antifoulings

Microfluidic Assay to Quantify the Adhesion of Marine Bacteria

An assessment of the ship drag penalty arising from light calcareous tubeworm fouling

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