2022 Fiscal Year Final Research Report
Comprehensive approach for estimating the drag reduction ratio of functional ship painting without the dependency of flow field
Project/Area Number |
20H02366
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Basic Section 24020:Marine engineering-related
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Research Institution | Yokohama National University |
Principal Investigator |
Takagi Youhei 横浜国立大学, 大学院工学研究院, 准教授 (40435772)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 船底塗料 / 水和型塗料 / 粘性摩擦抵抗 / 抵抗低減効果 / 流体制御 / 乱流 / 数値シミュレーション / 水槽試験 |
Outline of Final Research Achievements |
In order to investigate the function onset of hydrophilic painting with frictional drag reduction effect that is dependent on flow filed, the numerical analyses and resistance measurements for channel flow, Taylor-Couette rotating annular flow, and boundary layer on a flat plate were carried out. And also, the roughness effect was investigated and it becomes an import problem when the painting is used for ship hull. The hydrophilic painting showed the drag reduction effect if the surface had roughness, and an inhomogeneous roughness pattern led to enhance the effect. At the boundary layer, the state of laminar or turbulence was significant. At the condition without turbulence stimulation, the drag reduction was remarkable because the generation of spanwise rolling vortex seen in the transition of laminar-turbulent flow was suppressed by the hydrophilic painting.
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Free Research Field |
船舶海洋工学
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Academic Significance and Societal Importance of the Research Achievements |
船舶からの温室効果ガスの削減は重要な課題であり、燃費に直結する船体抵抗の多くは流体による摩擦抵抗が占めている。水和型の船底塗料は抵抗低減効果が確認されているが、その性能を最大限に引き出す利用方法が確立されていない。船体周りの流れは複雑であるため、本研究では抵抗に結び付く要因をいくつかの流れ場に対する数値的・実験的解析によって個々に抽出し、抵抗の増減に大きく寄与する因子を特定した。これにより、使用する船底塗料や船型形状、塗装する船体箇所によって抵抗を減らすための方法について一定の知見が得られ、新規塗料の開発や塗装方法について新しい提案ができることが見出された。
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