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

Study on the resistance performance of ships with moonpool
Xinyi YU1,2，Lilan ZHOU1,2
1. Key Laboratory of High Performance Ship Technology (Wuhan University of Technology), Ministry of Education, P. R. China.
2. School of Naval Architecture,Ocean and Energy Power Engineering, Wuhan University of Technology, P. R. China.
Wuhan, Hubei Province, P.R. ChinaABSTRACT

series of moonpool model tests at the Delft Ship Hydrodynamics
Laboratory to study the oscillation pattern of the water in the moonpool
and accumulated valuable experimental data. Hammargren et al. (2012)
performed numerical simulations of the two-dimensional moonpool,analyzed the flow field characteristics, and carried out a feasibility
study of three-dimensional moonpool resistance prediction based on thetwo-dimensional moonpool resistance. Liu et al. (2014) used the model
test and the CFD method to study the resistance characteristics of the
deep-water drilling ship with the moonpool. Huang et al. (2016)
adopted FINE/Marine to calculate the resistance of the drilling ship
when the moonpool was closed and opened at different speeds, thencompared with the model test results to study the additional resistanceof the moonpool. Yan et al. (2017) used CFD method, taking a salvage
ship as the research object, to carry out the numerical simulation ofships with or without moonpools, calculate the increase in resistancedue to moonpools, and study changes in wave making characteristics.

Studying the influence of moonpool on ship resistance to find effective
measures to reduce the resistance has become one of the focuses ofresearchers. In this study, numerical simulations have been made formodels with scale ratio λ=1:30 and λ=1:1 with and without moonpool
by using a RANS approach. The influence of moonpool on ship
resistance and the characteristics of resistance components with andwithout moonpool are discussed. The resistance predictions for modelwith scale ratio λ=1:1 based on different extrapolation methods and theresults of CFD simulation for model with scale ratio λ=1:1 arecompared, and the scale effect of the added resistance of moonpool isanalyzed.

KEY WORDS: moonpool; numerical simulation; resistance in calm
water; resistance extrapolation; scale effect

There also have some researches about different shapes of moonpool
and their drag reduction effects. Sadiq et al (2008) conducted a study
on two-dimensional, three-dimensional cylindrical and square
moonpools using CFX under a uniform flow situation, and the results
showed that the form of moonpool had a large effect on the shape ofvortex and the hydrodynamic force of the moonpool. Huang et al.
(2020) compared the fluid motion characteristics in different
rectangular moonpools by the experimental method. Zhan et al. (2020)
analyzed the influence and mechanism of the moonpool on the hull
resistance by computational fluid dynamics methods. At the same time,
the stepped-type and angle-cut-type moonpools are used as examples toverify the drag reduction effect. Yao et al. (2020) studied the unsteadyflow characteristics in moonpools of different shapes and analyzed thereasons of the additional resistance and also discussed its influence. Liet al. (2015) conducted a regression analysis of the added resistance ofthe straight-wall moonpool. Sivabalan et al. (2017) discussed
experimental and numerical study on moonpool with different cut-out
angles facing the head on side of incoming waves, aiming at
minimizing the water motion inside the moonpool under the response to
the incident waves.

INTRODUCTION
In order to meet the needs of underwater drilling operations and ensure
the safety of operating equipment and operators, the moonpool
structure is often arranged in the middle of the drilling ship, which
vertically runs through the main body of the structure, and there is afree liquid surface. At the same time, the water inside the moonpool isconnected with the outside sea water. During the movement of thedrilling ship, to some extent, the hydrodynamic performance of it will
be affected by the interaction of external and internal fluid. At present,
many scholars at home and abroad have carried out many researches on
moonpool, including the influence of the moonpool on the hull
resistance and motion performance, the analysis of the hydrodynamicperformance of the fluid in the moonpool and so on.
Many scholars have carried out researches to study the characteristicsof the moonpool and analyze reasons for increasing resistance on ship
affected by the moonpool. Aalbers et al. (1984) investigated thehydrodynamics of the moonpool and established the equations ofmotion of the fluid inside the moonpool in waves. Faltinsen (1993)
studied the piston motion characteristics of the fluid in thetwo-dimensional moonpool, and obtained the natural period of thepiston motion of the fluid in the moonpool. Cotteleer (2000) did twoBecause of the scale effect, many scholars directly conducted
researches on full scale ships to explore the feasibility of numerical

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