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Marine Dynamics Research Group

MARINE DYNAMICS

 This 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, this group conducts various experiments depending on the purpose as follows:

  • Experiments in the actual sea model basin using the free-running 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 the deep sea basin.
  • Actual sea area experiments for large ships and small planning boats.
 This group conducts analysis and investigation of the causes of marine accidents and technically responds to international and domestic standards for safety. This group also carries out research projects inside and outside the institute and undertakes various contracts and joint research. This group hopes that its activities contribute to developing 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 carried out by our group and the recent technical topics.


1. Development of Auxiliary Thrust Device for Model Test
— 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 full scale ship, even if the model ship has the same shape as the full scale ship, the phenomena of the model ship will not always be the same as that of the full scale ship. Ship resistance is one such phenomenon. 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 a self-propulsion test device simulating the main engine characteristic —

 To investigate the propulsive performance of an actual ship, a tank test using a model ship with the same geometrical shape is conducted. 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 load strength. To conduct more "real" model tests, we made a motor that reproduces the actual response of the engine. We have developed a method to directly check the propulsion performance of a full scale ship in a model test by devising a control method for 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 full scale ship, the phenomena that occur in the model ship are not always the same as those in the full scale one. The turning motion during steering and the change in speed due to wind and waves are such phenomena. We found a way to solve this problem and investigate the actual movement of the full scale 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 maneuvering simulation
  • An application of the 3-D seakeeping theory for a study on the fluctuation mechanism of flow fields around rotating propellers in waves and the 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 the development of automatic adaptive control technology for marine propulsion plant in the actual sea using tank test
  • Advancement of tank test methods for actual sea performance estimation
  • Study the influence of motion history of a ship that makes a turning motion while swaying in waves