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Marine Dynamics Research Group

MARINE DYNAMICS

 The Marine Dynamics Research Group conducts a wide range of research on the maneuverability performance of moving bodies in the ocean focusing on ships, including research on new-type ships such as advanced sail-assisted ships and technological development of underwater robots.
 In these studies, we conduct various experiments depending on the purpose as follows:

  • Experiments in the actual sea model basin using free-running model and captive model.
  • Captive model experiment in 400m towing tank/150m towing tank.
  • Load measurement/visualization experiment in pulsating wind tunnel with water channel.
  • Underwater robot experiments in deep sea basin.
  • Actual sea area experiments for large ships and small planing boats.
 We conduct analysis and investigation of the causes of marine accidents, and technically responds to international and domestic standards for safety. We also carry out research projects both inside and outside the institute, and undertakes various contracts and joint research. We hope that our activities contribute to the development of safe and advanced maritime technology.


Members

(◎: Head of the Group)

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Research Overview

Here, we would like to introduce some research themes being carried out by our group and the recent technical topics.


1. Development of Auxiliary Thrust Device
— To control (apparent) resistance of model ship at will —

  The good thing about model experiments is that you can directly measure actual phenomena. However, since the model ship is much smaller than the actual ship, even if the model ship is made to have the same shape as the actual ship, the phenomena of the model ship will not necessarily be the same as that of the actual ship. Ship resistance is one of such phenomena. We solved this problem and created a device that can control the apparent resistance of a model ship.



2. Direct Evaluation of Ship Speed Decline and Fuel Consumption in Actual Sea Area
— Development and application of self-propelled device with simulating the main engine characteristic —

 In order to investigate the propulsive performance of an actual ship, a tank test using a model ship with the same geometrical shape is conducted. And when conducting a model test, it is usual to control the motor to keep the rotation speed of the propeller constant. However, the engine speed of the actual ship changes depending on the the load strength. To conduct more "real" model tests, we made a motor that reproduces the actual movement of the engine, and have developed a method to directly check the propulsion performance of an actual ship in a model test by devising a control method of the motor.



3. Steering Effect Speed Correction
— To make the motion of a model ship similar to that of a real ship —

  Even if the model ship is made to have the same shape as the actual ship, the phenomena that occur in the model ship are not necessarily the same as the phenomena that occurs in the actual ship. The turning motion when steering and the change in speed due to wind and waves is actually one of such phenomena. We found a way to solve this problem and to investigate the actual movement of the ship in an experiment using a model ship.



Other Research

  • Variation of steady wave forces and moment acting on a ship due to the oblique motion and the influence on manoeuvring simulation
  • An application of the 3-D seakeeping theory for a study on fluctuation mechanism of flow fields around rotating propeller in waves and development of its simple estimation method
  • Study on clarification of performance required to avoid collisions of ships and criteria for prevention of accidents
  • Study on development and standardization of ship maneuverability evaluation method necessary for safe operation
  • Study on development of accident analysis and prevention technology to contribute to the prevention of marine accidents
  • Study on development of automatic adaptive control technology for marine propulsion plant in actual sea using tank test
  • Advancement of tank test methods for real-water performance estimation
  • Study on the influence of motion history of a ship that makes a turning motion while swaying in waves