Scaling of wetted-transom resistance for improved full-scale ship performance predictions
Journal article, 2022

Determining a ship's propulsive power is a critical stage in the design phase in which the evaluation of the stern plays a crucial role. Different flow regimes can be observed depending on the position and shape of the transom. This paper investigates the wetted-transom flow characteristics and their implications on the 1978 ITTC Performance Prediction Method. In the case of flow separation, such as the wetted-transom flow, the current ITTC-78 procedure does not provide an alternative method. Therefore, two alternative methods were proposed based on the investigations of CFD computations on seven hull forms. The firstly proposed method is a combined EFD&CFD method called the two form factor method. It requires CFD computations in model and full-scale, and it can handle any case of flow separation, including the wetted-transom flow. The second proposed method is an empirical correction formula for the hulls with a wetted-transom flow. Finally, the full-scale speed-power relations between the speed trials and the full-scale predictions from the two alternative methods and the standard ITTC-78 method were presented. It is observed that the two suggested methods considerably improve the correlation between the predictions and the speed trials.

Ship resistance



Combined CFD/EFD methods

Transom flow

Form factor


Kadir Burak Korkmaz

SSPA Sweden AB

Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology

Sofia Werner

SSPA Sweden AB

Rickard Bensow

Chalmers, Mechanics and Maritime Sciences (M2), Marine Technology

Ocean Engineering

0029-8018 (ISSN)

Vol. 266 112590

Areas of Advance


Subject Categories

Energy Engineering

Ocean and River Engineering

Fluid Mechanics and Acoustics



More information

Latest update