CFD analysis of the increase in ship resistance due to biofouling growth represented by roughness length scale

Abstract

Fuel consumption is heavily influenced by ship resistance, which mostly consists of friction resistance. During her operation, a ship is susceptible to the attachment of biofouling to its hull. The arbitrary form of biofouling induces an increase in surface roughness, which is responsible for the increase in friction resistance. This research analyses the increase in skin friction resistance due to biofouling, that is represented by a few variations of roughness length scale, in various orders throughout the models. Two-dimensional models of flat plates are utilized to investigate this issue by means of computational fluid dynamics (CFD) analysis. This study uses models with 0.56 m length to be tested in five Reynolds numbers, to be compared to a similar experiment conducted by using wind tunnel. Other models include 30 m and 60 m length to be tested in two Reynolds numbers each. It is found that the increase in skin friction reaches 3.5 – 31.4% for 0.6 m, 68.1 – 206.9% for 30 m with extreme regular roughness and 117.3 – 129.3% for 30 m with extreme irregular roughness, and 59.5 – 179.6% for 60 m with extreme regular roughness and 123.5 – 128.9% for 60 m with extreme irregular roughness.