Abstract

Precise information of viscous flow field around propeller is required to design energy saving devices equipped near ship stern. This work presents the detailed flow field measurement data around rotating propeller. The measurements were done using LaVision stereo Particle Image Velocimetry (PIV) system. The model ship used in the work is Japan Bulk Carrier (JBC) with/without round shaped small duct equipped at the upstream position of propeller as an energy saving device (ESD). In this paper, measured mean flow field upstream/downstream of rotating propeller with/without duct are presented and the turbulent kinetic energy at one station is also discussed. These data set would be useful to consider the availability of the basic idea of the device and to validate the theoretical prediction of the performance development including advanced CFD (Computational Fluid Dynamics) computation results in respect of accuracy. Overall, this study will be helpful to design duct-type ESD.

Introduction

Recently, regulations to limit the emission of CO2 from ocean going ships, known as Energy Efficiency Design Index (EEDI), has been a central topic of discussion and utilization of energy saving technology has been widely progressed. Since almost all the energy saving devices are equipped around propeller (e.g. pre-swirl fin optimizing flow velocity into propeller, rudder with horizontal fin assisting to produce thrust using rotational flow in propeller slipstream, and etc.), accurate information of viscous flow field near propeller is required to design them due to the complicated interaction between propeller, rudder and stern flow field with strong vorticity. Recently, CFD has been applied to analyze the flow field around ship stern with ESD but the verification of the computational results is still insufficient mainly due to the lack of detailed measurement data around propeller with ESD. Although the measured data and comparison with CFD results are presented in some papers (e.g., Jie Dang et al., 2012 and Nagaya et al., 2011), the detailed geometry of ship model, propeller, rudder, ESD and data set are usually not available for public use. Therefore, the data set for CFD validation for present geometry was taken from Tokyo CFD Workshop which is open to public for validation (Hino et al., 2015).

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