Hydrodynamic Analysis for a Floating Kuroshio Turbine in Vertical Shear Flow

• Main Authors: Shih-Hao Lin, 林師豪
• Other Authors: Forng-Chen Chiu
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/5kfqnj

碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 105 === In general a marine current flow is not uniform. Therefore, when a Floating Kuroshio Turbine (FKT) operates in it, not only the hydrodynamic performance may be affected, but also the hydrodynamic loads acting on the blade may vary with time. In this way, the hydrodynamic loads may induce damage to blades due to resonance or fatigue failure. Therefore, hydrodynamic loads acting on blades operating in vertical shear flow were investigated in the present study. In this present study, the CFD software ANSYS-FLUENT is applied to deal with the hydrodynamic problems. To simulate the velocity distribution of Kuroshio Current, linear vertical shear flows are adopted for simplification. First of all, steady-state simulation is applied to analysis the hydrodynamics for single turbine and full FKT in vertical shear flow. Meanwhile, in this simulation, the effects of turbulent intensity to the hydrodynamics of single turbine are also discussed. Finally, unsteady-state simulation is applied to deal with the hydrodynamics for single turbine operating in vertical shear flow, the time varying hydrodynamic forces and moments acting on the blade root are investigated. The numerical results show that the hydrodynamic performance of single turbine or full FKT is not affected significantly by vertical shear in the flow. However, the amplitudes of time varying hydrodynamic forces and moments acting on the blade root become more significant with the increase of velocity gradient of the vertical shear in the flow. It means that these hydrodynamic loads should be taken into consideration in blade structure design.