Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Numerical Simulation of the Ship Turning in A Seaway with Consideration of the Limit of Propulsion
PowerWei Zhang, Rongze Guo, Guanghua He
School of Ocean Engineering, Harbin Institute of Technology (Weihai),Weihai, Shandong, China PR

seaway, it is deemed important to investigate the ship maneuvering inirregular waves. Nevertheless, there are only a few published studies
dealt with the ship maneuvering in irregular waves. (e.g. Yasukawa etal, 2015; Seo et al. 2018).

ABSTRACT
A mathematical model was proposed for simulating the shipmaneuvering in a seaway. The mean wave drift forces and moment due
to irregular waves were added into the MMG model to simulate thewave effects. The influences of the limited propulsion power on theship maneuverability was also accounted for. Numerical simulations
were performed using a full scale S-175 container ship under sea states
4 and 5. The results showed that a limit of propulsion power may
significantly attenuate the ship turning ability, especially in high seastates.

Moreover, many new ships built in recent years chose to decrease theinstalled propulsion power to fulfil the requirement of Energy
Efficiency Design Index (EEDI). Since an underpowered ship may losemaneuvering capability under adverse weather condition, it is necessary
to examine the ship maneuvering in waves with consideration of thelimited propulsion power. However, because of the complexity of theissues, related study has been rarely reported, except for a recent studyof Suzuki et al. (2019) that investigated the course keeping ability ofthe KVLCC ship in regular waves with a consideration of theoperational limit of an engine.

KEY WORDS: Maneuvering; Irregular waves; Wave drift loads;
Minimum Propulsion Power, Full-scale ship.

INTRODUCTION

Basically, turning maneuver is one of the most typical maneuvering
motions of the ship. In present study, we conduct numerical simulationsof the ship turning maneuvers in irregular waves. And a limited
propulsion power is accounted for in order to simulate the scenario thatthe ship is in an underpowered condition. Numerical simulations areperformed based on a modular-type MMG maneuvering model. The
wave drift loads due to irregular waves, determined by a precomputed
database, are added into the MMG maneuvering model to simulate thewave loads of a seaway. The limits of the propulsion power aremodelled by locking the operational region on the load diagram of theengine.

Ship maneuvering in waves has been increasingly investigated in recentyears. Although the physical experiment is still regarded as the mostreliable way to investigate ship maneuverability in waves, there are
more and more studies providing practical mathematical models of shipmaneuvering prediction. Generally, the state-of-the-art methods forpredicting the ship maneuvering in waves can be classified into themethod based on the mathematic model and the method based on thedirect CFD simulation.
The mathematic model of ship maneuvering in waves are typicallyformulated by encapsulating the calm water maneuvering model andthe wave loads. Related studies have been conducted, for example, bySkejic and Faltinsen (2008), Seo and Kim (2011) and Zhang et al.
(2017). CFD methods in principle provide an adequate description ofall physics. Based on the CFD simulations, Uharek and CuraHochbaum (2016) and Yao et .al (2020) computed mean wave drift
loads on the maneuvering ship in regular waves. Carrica et al. (2013)
and Wang and Wan (2020) conducted the direct CFD simulations of theturning, zigzag and stopping maneuver of free running ship in waves.

MATHEMATICAL FORMULATIONS
Coordinate Systems
Two right-handed coordinate systems are adopted, as shown in Fig. 1.
The first one x  ( x, y, z) is a reference frame which moves withthe speed of ship maneuvering motion, with the positive x towards thebow and the positive z pointing upward. The xy plane is always
coincident with the calm water level and the origin of the frame is at themidship; the second one X  ( X ,Y , Z ) is a global frame fixed in space.
The two coordinate systems coincide at the initial instant and have theAlthough these investigations provided useful tools for analyzing theship maneuvering in waves, most of them were limited to regular wave
scenario. For a better understanding of the ship maneuverability in a3734