2020 Fiscal Year Final Research Report

Development of perfomance evaluation method for energu saving devices of a ship using boundary layer Similarity model

Research Project

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Project/Area Number	19K22013
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 24:Aerospace engineering, marine and maritime engineering, and related fields
Research Institution	Yokohama National University
Principal Investigator	Hino Takanori 横浜国立大学, 大学院工学研究院, 教授 (60373429)
Project Period (FY)	2019-06-28 – 2021-03-31
Keywords	船舶流体力学 / 省エネルギーデバイス / CFD / 境界層
Outline of Final Research Achievements	The new method has been developed which enables the propulsive performance evaluation of energy saving devices of an actual ship by using model test. In order to overcome the difficulty associated with the scale effect of the boundary layer thickness between full-scale and model scale-ships, a special model called the Boundary Layer Similarity model (BLS) was conceived. The model is designed to reproduce the aft-part of a ship only and to have the same boundary layer thickness ratio as an actual ship. Using this model, it is possible to achieve the geometrical similarity and the hydrodynamic similarity for the performance evaluation at the same time. Simulations by Computational Fluid Dynamics are applied to assess the flow fields and the propulsive performance of an energy saving device for the usual model ship, full-scale ship and the BLS. It turned out that the results of the BLS are in good accordance with the full-scale results and the validity of the new method was confirmed.
Free Research Field	船舶海洋工学
Academic Significance and Societal Importance of the Research Achievements	模型試験による船舶の省エネルギーデバイスの推進性能評価は、模型船と実船のレイノルズ数の差に起因する尺度影響が不可避であった。実際、模型試験では良好な性能が確認された省エネルギーデバイスが実船では期待された効果を発揮しない例も見られる。本研究では、計算流体力学手法による粘性流れシミュレーションを活用して尺度影響を評価し、模型船において実船の流れを再現する新しい性能評価法を提案した。本研究成果により、流体力学的相似性と幾何的相似性を同時に満たす模型試験が可能となり、船舶の省エネルギー性能のさらなる向上によって温室効果ガスの削減を推進するものと思われる。