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

Research on Resistance Reduction Technology for Multiple Ship Formations
Zhicheng Zhang1, Jianglong Sun1,2,3*
1. School of Naval Architecture and Ocean Engineering (HUST), Wuhan, Hubei, China
2. Hubei Provincial Engineering Research Center of Data Techniques and Supporting Software for Ships (DTSSS), Wuhan, Hubei, China
3. Collaboration Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE), Shanghai, China

fuel. Therefore, studying the problem of ship drag reduction is an
important direction for studying the problem of ship energy saving (Tu;Yang; Zhang; Lyu; Song; Guan; Sun. 2018). At present, many scholars
have done a lot of research on various ship resistance reduction methods(Hu. 2018).

ABSTRACTThis paper proposes and validates a multiple ship formation resistance
reduction method, designs a suitable fleet formation, and analyzes theobjective reasons of formation resistance reduction.

Bulbous bow drag reduction technology. The drag-reduction and energysaving bulbous bow can effectively reduce the wave-making resistance.
According to preliminary research, the drag-reduction and energy-saving
bulbous bow can achieve excellent drag reduction effect (more than 15%
energy saving), and has broad application prospects. The installation of
new energy-saving bulbous bows on high-speed surface ships is a
frontier subject of research at home and abroad in recent years. (Zhang;Lu. 2017)

In the first part of this paper, a 300DWT oceanographic survey ship isselected for resistance calculation, and the obtained results arenumerically compared with the results of the ship model resistance test
carried out in the towing tank. The second part of this paper designs theship formation scheme, and calculates the resistance again under theappropriate formation scheme. The third part of this paper compares theresistance calculation results of the first two parts, verifies the dragreduction effect of the multi-ship formation, and briefly analyzes thereasons.

The best trim drag reduction technology. Under the condition of a certain
load, when the trim changes, the length of the hull waterline and theunderwater geometry change, resulting in changes in resistance andpropulsion efficiency. When the displacement and speed are constant,
there is an optimal trim state. The power required in this state is minimal.
When the ship sails in the optimal trim state, the hull resistance isreduced, and the propulsion efficiency is improved, which can greatly
save the power of the main engine (Lin; Yu. 2008).

KEY WORDS: multiple ship formations; ship resistance; resistance
reduction technology; CFDINTRODUCTION
For the shipping industry, reducing the energy consumption of ships hasalways been a hot research issue. From an economic point of view,
general water transport routes are longer and time-consuming. On theone hand, reducing the energy consumption of ships can effectively
reduce the cost of fuel, on the other hand, it can reduce the amount offuel carried, further liberate the cargo space, and improve transportation.
From an environmental perspective, according to the second greenhousegas research report released by the International Maritime Organizationin 2009, the CO2 emissions of the shipping industry have reached 3.2%of the global CO2 emissions (Hao, Qiang, Shi, Suo, Xiao. 2012). Energy
conservation and emission reduction in the shipping industry will reducegreenhouse gas emissions to a certain extent, and have a certain
mitigation effect on natural disasters such as the greenhouse effect.

Rib drag reduction technology. As a kind of bionic non-smooth surface
drag reduction technology, rib drag reduction technology has become aresearch hotspot of researchers in recent years. The rib drag reduction
technology achieves the effect of drag reduction by changing the shapeof the wall surface of the object in contact with the fluid to change theturbulent structure of the rib near the wall area. A series of protruding ribstructures with a certain shape and size are arranged on the surface of theobject in an orderly manner to form a non-smooth drag reduction surface(Liu; Yu; Wang; Zhang; Li. 2016).
Air curtain drag reduction technology. Since the 21st century, Chinese
universities and scientific researchers have proposed the ship air curtain
resistance reduction technology, which has changed the properties of thefluid on the surface of the hull, and used technical means to form an air
layer on the surface of the hull to reduce the resistance of the hull. The
principle of the air curtain drag reduction technology is to use the densityand viscosity difference between water and air to introduce air at thebottom of the ship to form a thin layer of gas-liquid two-phase mixed

The propulsion system is the main way of energy consumption for ships,
accounting for about 70% to 90% of the energy consumption of the entire
ship. In the ship propulsion system, the main engine burns fuel to transferenergy to the transmission, and then to the propeller (Sun. 2012). The
propeller rotates to overcome the resistance and do work to propel thesailing. From this process, it can be seen that the resistance experienced
by the ship while sailing directly affects the consumption of energy and3462