Fluid Control Research Group

Update 2008.7.14

Japanese page

Overview

Air injected into water surrounding a running ship from its bottom can reduce friction drag acting on a ship advancing in water. So drag reduction by air injection method has been researched as promising friction reduction devices for ships. Many experiments using a very long ship model with large flat bottom and full scale ship have demonstrated significant friction reduction effect for practical use for the low speed vessel with large flat bottom. But at the same time, experiments have indicated big problems for practical use such as disturbance of bubbles to the propulsive efficiency of propeller. We therefore conduct researches to clarify problems for practical use of an air-injection method and to prove potential of utilization of this method by full scale ship experiments.

Member

Research Titles

Research and Development of Energy-saving Technology for Ship by use of Microbubbles

Study of Reduction of Frictional Resistance by use of Microbubbles under Very High Speed Condition

Center for Smart Control of Turbulence (July 2000 - May 2005)

Many researchers from three independent administrative research institutes (National Aerospace Laboratory of Japan, National Institute of Advanced Industrial Science and Technology and National Maritime Research Institute), and several universities (Kogakuin University, The University of Tokyo, Tokyo Institute of Technology, Keio University, Aoyama Gakuin University and so on) cooperated under the same purpose which is to develop smart control turbulence, i.e. complex fluid phenomenon financed by the Ministry of Education, Culture, Sports, Science and Technology the Study for Organized Research Combination System (ORCS) with Special Coordination Funds for Promoting Science and Technology: "Smart Control of Turbulence: A Millennium Challenge for Innovative Thermal and Fluids Systems" (2000-2004). This project attained enormous accomplishments. "Center for Smart Control of Turbulence" was established at NMRI, the project organizer during project years, was carried out by over 60 researchers as the members of the center, which contributed to implement researches effectively as well as systematically. At NMRI, as part of this project, we conducted the study of microbubbles and lean premixed combustion.

The Committee for Smart Control of Turbulence(August 2005-)

The Committee for Smart Control of Turbulence has been inaugurated in order to develop outcomes attained by the Study for Organized Research Combination System. Please proceed to its page for more information.

Topics

Energy-saving by surrounding ships with microbubbles c. Drag reduction of ship by use of microbubblesc

Plain explanations of the princple and feature of the effect of microbubbles on drag reduction, and prospect of practical application of microbubbles are shown in the above link.

Experiment Equipment

Tunnel for basic experiment of microbubble.