2021 Fiscal Year Final Research Report

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

Research Project

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Project/Area Number	19H02369
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 24020:Marine engineering-related
Research Institution	National Institute of Maritime, Port and Aviation Technology
Principal Investigator	Kitagawa Yasushi 国立研究開発法人海上・港湾・航空技術研究所, その他部局等, 研究員 (50579852)
Co-Investigator(Kenkyū-buntansha)	柏木正大阪大学, 工学研究科, 教授 (00161026)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	船舶耐航性能 / 波浪中プロペラ推力・トルク / プロペラ有効流入速度 / 船体表面圧力 / 船舶操縦性能 / 非定常圧力
Outline of Final Research Achievements	Aims of this study is elucidating fluctuation-mechanism of flow fields around rotating propeller of ship, by applications of a numerical calculation method basing on the 3-D seakeeping theory and experimental investigations. Furthermore, based on results of these investigations, sophisticating the conventional model of the propeller effective inflow velocity in waves is also aimed. In the experimental investigations, some significant findings were obtained. For example, it was experimentally confirmed that effects of the propeller slipstream to fluctuation amplitude of hydrodynamic pressure on hull surface in waves are not significant. On the other hand, development and its validation of the numerical calculation method is not ended as initially planned, since co-researcher had to get out of this project. Therefore, as alternative investigations on the effects of the propeller slipstream, measurements of hull surface pressure in maneuvering motion were successfully done and analyzed.
Free Research Field	船舶耐航性能、船舶操縦性能
Academic Significance and Societal Importance of the Research Achievements	本研究では、一部の数値計算手法の開発は当初目標を達成出来なかったものの、波浪中模型試験による波浪中のプロペラ回転流影響の分析において、貴重な知見を多数得られた。これら知見は、速度ポテンシャルベースの耐航性計算手法の高度化において貴重な参考データとなり、ノンキャビ状態のプロペラ変動圧の評価については新しい知見を与えたものである。また、操縦運動中の舵表面を含んだ非定常圧力の計測を行えたことも含め、特にCFDによる自由航走直接シミュレーション手法の開発等、数値計算手法の高度化に貢献できる貴重データが得られたことは意義深いと言える。