This paper presents a comparison of the computation results of added resistance on ships in waves. Recently, the design of ships with less green-house gas is one of great interest in naval architecture fields. Ship designers need to find optimum hull forms with minimum resistance in ocean waves. Therefore, an accurate computation of added resistance is getting more important for the prediction of power increase on ships in random ocean waves. This study focuses on the numerical computation of added resistance in different methods. To calculate added resistance on ships in waves, three different methods are considered. One is a direct pressure integration method, another is a momentum conservation method, and the other is a radiated energy method. The direct pressure integration method and the momentum conservation method are combined with a higher-order Rankine panel method, and the radiated energy method and the momentum conservation methods are combined with the strip method. The computational results are validated by comparing them with experimental data on Wigley hull models, Series 60 hulls, and S175 containership. Reasonable agreements are observed for all the models. The study is also extended to the analysis of added resistance in short wave range. To complement the results of added resistance in short wave, the established asymptotic calculation methods are examined.


When a ship navigates in waves, the ship's forward speed decreases compared to that in calm sea because of the added resistance. It is reported that the magnitude of added resistance is about 15–30% of a calm-water wave resistance (Arribas, 2007). An accurate prediction of added resistance, therefore, is important in the design of a ship with propulsion power. Moreover, in recent years, discussions at International Maritime Organization (IMO) have resulted in the development of an Energy Efficiency Design Index (EEDI) to measure how much green-house gas a ship emits per unit transport provided and to restrict green-house gas emissions from ships.

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