Subject

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

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).

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.

Publications
 

• Candries M., Atlar, M. and Anderson, C.D. (2003), Estimating the impact of new-generation antifoulings on ship performance: the presence of slime, Proceedings of the Institute of Marine Engineering, Science and Technology, Part A: Journal of Marine Engineering and Technology, No. A2, pp. 13-22, IMarEst Publications, London.
• Anderson, C.D., Atlar, M., Candries, C., Callow, M.E., Milne, A. and Townsin, R.J. (2003) The development of Foul Release coatings for seagoing vessels, A Submission for IMarEST Marine Environment Award Queen�s Golden Jubilee Medal.
• Candries, M., Atlar, M., Mesbahi, E. and Pazouki, K. (2003), The measurement of the drag characteristics of Tin-free Self-Polishing Co-polymers and Fouling Release coatings using a rotor apparatus. Biofouling,Vol. 19 Supplement: Papers of the 11th International Conference on Marine Corrosion and Fouling, San Diego, Cal., 21-26 July 2002, pp. 27-37.
• Atlar M., Glover, E.J., Candries, M., Mutton, R.J. and Anderson C.D. (2002), The Effect of a Foul Release Coating on Propeller Performance, ENSUS 2002: International Conference on Marine Science and Technology for Environmental Sustainability, University of Newcastle-upon-Tyne, 16-18 December 2002, Newcastle-upon-Tyne.(PDF, 334kB).
• Candries, M and Atlar, M. (2002), Experimental investigation of the turbulent boundary layer of surfaces coated with marine antifoulings, submitted to ASME Journal of Fluids Engineering.
• Candries, M. (2001), Drag, Boundary-Layer and Roughness Characteristics of Marine Surfaces Coated with Antifoulings, PhD Thesis, December 2001, Department of Marine Technology, University of Newcastle-upon-Tyne, (Thesis, 3.5MB; Appendices, 3.3MB).
• M. Candries, M.Atlar, A. Guerrero and C.D. Anderson (2001), Lower frictional resistance characteristics of Foul Release systems, Proceedings of the Eight International Symposium on the Practical Design of Ships and Other Floating Structures, Volume 1, pp. 517-523, Elsevier, Amsterdam.
• M. Candries, C.D. Anderson and M. Atlar (2001), Low-energy surfaces on high-speed craft. Proceedings HIPER '01, Hamburg, 3 May 2001. (PDF, 222kB).
• M. Candries, C.D. Anderson and M. Atlar (2001), Foul release systems and drag. Proceedings PCE 2001, Antwerp, 28 March 2001. (PDF, 302kB).
• M. Candries, M. Atlar and C.D. Anderson (2000), Considering the use of alternative antifoulings: the advantages of foul-release systems, Conference Proceedings ENSUS 2000, pp. 88-95, Departments of Marine Technology and Marine Sciences, University of Newcastle-upon-Tyne, UK. (PDF, 224kB).
• M. Candries (1998), Recent developments in surface technology and the effect on roughness and drag, MSc Dissertation, University of Ghent (Completed at the University of Newcastle-upon-Tyne under the Erasmus/Socrates European Exchange Programme), Belgium. (1007 KB, available on request)

Reports

• M. Atlar, E.J. Glover and M. Candries, Calculation of the effects of blade roughness on the performance of the propeller of M/T Guardian, Department of Marine Technology Report No. MT-2002-003, University of Newcastle-upon-Tyne, February 2002.
• M. Candries and M. Atlar, Experiments with a wavepiercing catamaran model : the effect of three different paints, Department of Marine Technology Report No. MT-2000-067, University of Newcastle-upon-Tyne, November 2000.
• M. Candries and M. Atlar (2000), Influence of two different antifoulings on the resistance and roughness of a flat plate, Department of Marine Technology Report No. MT-2000-012, University of Newcastle-upon-Tyne, May 2000.
• M. Atlar, M. Candries and I. Paterson (1999), Coating performance tests with model propeller no. ECT101, Department of Marine Technology Report No. MT-1999-021, University of Newcastle-upon-Tyne, July 1999.
• M. Candries, M. Atlar, G.H.G. Mitchell and D. Lamb (1998), Flat plane towing experiments with two coatings. Department of Marine Technology Report No. MT-1998-034, University of Newcastle-upon-Tyne, October 1998.

Presentations

• M. Candries and M. Atlar (1999), Review of drag reduction techniques for long-term marine application: considering the combination with novel anti-fouling systems. In: Z. Chara  and J. Pollert (Eds.), Proceedings of the 11th European Drag Reduction Working Meeting, Institute of Hydrodynamics, Prague, September 15-17, 1999.
• M. Candries (1999), Recent Developments in Surface Technology and the Effects on Roughness and Drag. Joint Winner of the 1999 KBUSI/URBIN Price for Final Year Dissertations in Marine Technology, presented at the Sofitel Hotel, Antwerp, 27 April 1999.
• C.D. Anderson, R.L. Townsin and M. Candries (1999), Idiosyncracies of low surface energy (foul-release) antifoulings: drag, roughness and maintenance. Presented at the 10th International Congress on Marine Corrosion and Fouling, Melbourne, Australia, 8-12 February 1999. Presented by C. Anderson.

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