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

Wave Drift Load Analysis of Ships with Drift Angle in Oblique Waves
Guo-Dong Zhang, Ji-Kang Chen*, Wen-Yang Duan, Meng-Yuan Zhu
College of Shipbuilding Engineering, Harbin Engineering University.
Harbin, Heilongjiang Province, China

ABSTRACT

Guo and Steen (2011) conducted model tests for the surge wave drift
force on KVLCC2. Park et al. (2018) completed experiments under theoblique waves to measure the added resistance on a tanker, and wave
direction was changed from 180° to 0°. Seo et al. (2021) measured
surge and sway wave drift forces and yaw drift moment of theKVLCC2 model ship under different wave direction by a direct method
using force sensors, and an indirect method using tensiometers. The
measurement results of these two methods differ obviously when thewave length-to-ship length ratio is small. With the development ofcomputer technology, CFD (the Computational Fluid Dynamics)method is widely used in solving nonlinear response of ship and addedresistance. However, there are few scholars use CFD method to solve
sway wave drift forces and yaw drift moment of a ship in oblique
waves, the main reason is that CFD method is seriously timeconsuming, and unsuitable for routine ship design applications (SadatHosseini et al. 2013; Tezdogan et al. 2015; Sigmund et al. 2018). In
comparison, the potential flow method based on the Rankine panel
method with forward speed is more robust and efficient. Using aRankine panel method, Lyu et al. (2017) obtained surge wave driftforce (added resistance), sway wave drift force and yaw wave drift
moment coefficients for a containership and a cruise ship at shipheading angles from 0 to 180deg. Yasukawa et al. (2019) calculated thewave drift load using a zero-speed, three-dimensional panel method
and a strip theory based Kochin function method and the calculated
results are in good agreement with the experimental results. Zhang et al.
(2020) calculated the second-order drift load of model ships at zero
speed and with speed based on a time Romain Rankine panel method.
Seo et al. (2021) used the frequency domain Rankine panel method tocalculate the second-order wave drift load of KVLCC2 model ship
under different waves, and compared it with the experimental value.
The results show that the numerical results are in good agreement when
the wave length-to-ship length ratio is large. These only calculated thesecond-order wave drift load of ships under different waves, ignoring
the existence of ship drift angle.
In the paper, based on TEBEM method (Duan et al., 2020), surge
wave drift forces, sway wave drift forces, yaw wave drift moment and6-DOF motions of KVLCC2 model ship with 120 ° wave direction anddifferent drift angle are calculated. The rest of the paper is arranged asfollows. A briefly introduction of the mathematical formulations ofboundary value problems and TEBEM method is presented in thesecond part. Numerical results and discussions are given in the thirdpart. The final part shows the conclusions based on the results.

The calculation of ship wave drift load is of great significance to theprediction of ship maneuvering motion. Current studies on the wave
drift load of ships mainly focus on the case of zero drift angle (Seo etal., 2021; Chen et al., 2021), however, in the real sea states, the ships
move with a certain drift angle. In this paper, TEBEM method (Taylorexpansion boundary element method) is used to calculate surge andsway wave drift forces and yaw drift moment of a ship with drift angle
in oblique waves, and the comparison is made with the wave drift loadof a ship without drift angle. Finally, the influence of drift angle onsecond-order wave drift load of ship is analyzed in detail. When thewave length-to-ship length ratio is small, the surge drift force decreases
and the sway drift force increases with the increase of drift angle, andthe drift angle have minor effect on yaw drift moment.

KEY WORDS: Wave drift load; TEBEM method; Drift angle;
Oblique wave.

INTRODUCTION
In addition to the first-order wave force, the ship with speed in thewave will also be subjected to the second-order wave drift load. In
recent years, with the attention paid to the energy consumption of ships
and the maneuverability of ships in waves, the surge drift forces (addedresistance) have been extensively studied. However, there are few
studies on the sway wave drift forces and yaw drift moment of a ship in
oblique waves, and even less on the second-order wave drift load ofships with drift Angle in oblique waves. However, under severe sea
conditions or rolling resonance, the sway drift force and the yaw drift
moment may become very large and have a great influence on theship's maneuvering. Moreover, the ship usually has a certain drift angle
when moving under real sea conditions, and the existence of drift angle
will affect the calculation of second-order wave drift load. Therefore,
in order to improve the prediction accuracy of ship maneuverability inwaves, it is very important to study the second-order drift load of ships
with drift angle in oblique waves.
At present, the research on second-order wave drift load of ships
mainly focuses on the following three aspects, which are experimental
method, the computational fluid dynamics (CFD) method and thepotential flow method. The experimental method is still the mostreliable method to measure the second-order wave drift load of ships.

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