Abstract

To develop a better understanding of ‘in-service’ performance of modern marine coatings, this study explored the combined effects of different roughness ranges of foul-release coating (FRC) and light biofouling (slime) on the surface, boundary layer and drag characteristics under a range of ‘in-service’ conditions. Natural and laboratory biofilms were grown dynamically on FRC panels by exposing panels in facilities dedicated to realistic fouling culture. The boundary layer experiments were conducted in a circulating water tunnel. Boundary layer similarity-law scaling was used to predict the combined effects of coating roughness and biofilms on the added frictional resistance (%${\Delta C}_F)$ and added required effective power ${\mathrm{ }(\mathrm{\%}\Delta P}_E$) for a benchmark KRISO container ship (KCS) and a bulk carrier. The increase in${\mathrm{ }\mathrm{\%}\Delta P}_{E\mathrm{ }}$ due to the presence of biofilms on commercial FRC is estimated to be between 7% and 16% depending on the biofilm type, biofilm thickness and percentage coverage. Significant increases in effective power are estimated for non-fouling control primers with heavy fouling. Moreover, the paper suggests updated roughness allowances (${{\Delta C}_F}_{}$) for two vessel types assuming FRCs on their hulls with more representative hull roughness ranges and fluffy biofilms.

摘要

为了更好地理解现代船用涂料的“使用中”性能，本研究探索了污垢释放涂层（FRC）和轻度生物污损（粘液）的不同粗糙度范围对表面，边界层和阻力特性的综合影响。在一系列“使用中”条件下。通过在专门用于实际污垢培养的设施中暴露面板，天然和实验室生物膜可以在FRC面板上动态生长。边界层实验是在循环水隧道中进行的。边界层相似律定标用于预测涂层粗糙度和生物膜对增加的摩擦阻力的综合影响（％${\Delta C}_F）$ 并增加了所需的有效功率 ${\mathrm{ }（\mathrm{％}\Delta P}_{Ë}$）用于基准KRISO集装箱船（KCS）和散货船。增加${\mathrm{ }\mathrm{％}\Delta P}_{Ë\mathrm{ }}$由于生物膜在商业FRC上的存在，根据生物膜的类型，生物膜的厚度和覆盖率的百分比，估计为7％至16％。估计严重结垢的非结垢对照底漆的有效功率显着增加。此外，该论文还建议更新粗糙度容限（${{\Delta C}_F}_{}$）对于两种船型，假定船体上的FRC具有更典型的船体粗糙度范围和蓬松的生物膜。