Author(s)

I Ketut Aria Pria Utama, Bagus Nugroho, Jason Monty, Nicholas Hutchins, Bharathram Ganapathisubramani

Corresponding Author

I Ketut Aria Pria Utama

ABSTRACT

This work discusses the efficacy of different drag penalty estimation techniques in predicting the percentage change in the average skin friction coefficient due to ship hull roughness. This includes comparing the traditional predictive method from ITTC that is currently used by the shipping industry with the recently developed estimation technique that incorporate average roughness height ka and effective slope ESs. Here the two methods are tested using a biofouling roughness case from experiments that utilize the well-known classical log-law from mean velocity profiles and the integral formulation of evolving turbulent boundary layers. The results show that the traditional estimation method from the industry can differ by approximately 15% compared to the experiment, while the more recent estimation technique differs by around 2% with respect to the experimental result. The result demonstrates that the ka and ESx based empirical technique may have potential for estimating realistic ship-hull roughness such as biofouling.

KEYWORDS

Shiphull Drag Penalty, Turbulent Boundary Layer, Surface Roughness, Drag Penalty Estimation.