Drag, boundary-layer and roughness
characteristics of marine surfaces
coated with antifoulings

PhD Research Project
Maxim Candries



A Review on Marine Paints

Emerson Cavitation Tunnel         Engineering Design Centre

Turbulence Maillist Website

Last updated: December 5, 2005.


The frictional resistance characteristics of a Foul Release coating have been compared with those of a Tin-free Self-polishing Co-Polymer, which is an IMO-compliant but toxic antifouling system. Measurements of the roughness characteristics have been correlated with drag measurements obtained from towing tank and water tunnel experiments.

Water tunnel experiments

The two-component two-beam LDV equipment measures
the turbulent boundary layer over a sand-roughened surface.

First Series

Water tunnel experiments have been carried out to measure the turbulent boundary-layer characteristics of the different coatings with laser-doppler velocimetry (LDV). The LDV equipment measures the boundary-layer velocity profile over a flat plate set-up and allows the indirect calculation of the roughness functions over the different painted surfaces using the Clauser method (as modified by Perry et al.), the Hama method and the Reynolds-stress method. Five test plates have been tested: steel (smooth), SPC, Foul-release (sprayed and rollered) and Sand-grit. The roughness functions have been correlated with a combination of roughness parameters. The roughness parameters have been measured with both a stylus instrument (the standard BMT Hull Roughness Analyser for ship hulls) and a non-intrusive optical instrument.

Second Series

Experiments under the European TMR programme at the CEHIPAR Cavitation Tunnel in El Pardo, Spain, carried out in May 2001.

Towing tank experiments

Three series have been carried out:

1. A 2.55m long plate was used for the experiments in the 40m long towing tank of the University of Newcastle-upon-Tyne (1998).

           Flat plane experiments in Newcastle University Towing Tank

2. A 1/35-scale model of a narrow hull 115m wavepiercing catamaran was used for the experiments in the 65m long towing tank of the University of Strathclyde in collaboration with the University of Newcastle-upon-Tyne (1999 - 2000).

3. A 6.3m long plate was used for the experiments at the CEHIPAR Calm Water Towing Tank in El Pardo, Spain, for the University of Newcastle-upon-Tyne under the CEHMAR programme (March 2000).

The flat plate experiments have shown that the foul-release coating system is hydrodynamically smoother than  the SPC system.

Future prospects

The prospect of combining the foul-release coating with a drag reduction technique seems interesting in terms of long-term marine application. Particular attention is paid to passive techniques such as riblets and compliant coatings; both of which are also encountered in nature as shark scales and dolphin skin respectively.

My PhD research under the surpervision of  Prof. Mehmet Atlar was sponsored by EPSRC, EDC and International Coatings Ltd. The research project is ongoing and now focuses on the effect of coating propellers and the effect of slime films on the boundary-layer characteristics of coated surfaces.




Turbulence Maillist

Because of my research I am particularly interested in flow control, coherent motions and the effect of roughness on near-wall turbulence. In a desire to learn more, make contacts with colleagues and keep up-to-date, I created a  maillist devoted to turbulence on 15 March 1999

Maxim Candries
Fax: ++ 32 3 772 30 38
Created: 15/3/1999