Numerical Validation of Frictional Coefficient for a Flat Plate with Various Anti-Fouling Coatings

Abstract

Skin friction is responsible for approximately 60-70% of ship resistance. The fuel consumption and emission of the ship vary with the wetted surface, hull form and roughness. Reducing wetted surface area is not feasible and hence for reducing frictional resistance either the hull form should be optimized or the hull roughness function be made optimum. Most of the cases the hull form optimization of existing vessels are difficult and not economical. For these ships, the application of anti-fouling coating or air injection method below the bottom of the hull can be easily adapted to minimize the frictional resistance without any alteration on the vessel. The anti-fouling coating reduces the accumulation of marine growth and surface deterioration and hence limit the frictional drag. The selection of anti-fouling coating is also important since the resistance generated by the surrounded fluid on the ship increases with an increase in roughness function. This paper presents the numerical analysis and validation of frictional coefficient using CFD for different anti-fouling coating in the case of a flat plate. The roughness effects of different marine coatings are replicated and the frictional coefficient are compared with existing experimental data. The CFD results are agreeable with the published results. The work presented here could be applied to ship hulls to study the roughness effects due to various coatings or bio-fouling conditions to estimate the frictional drag and its effects in fuel consumption.