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| Hydrodynamic performance of ducted turbine under complex tidal current conditions |
| SONG Ke1*, YANG Bangcheng2 |
| 1. School of Mechanical and Electrical Engineering, Kunming University, Kunming, Yunnan 650214, China; 2. Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, Yunnan 650500, China |
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Abstract In order to explore the unsteady performance of ducted turbine under complex tidal current conditions, the effects of immersion depth and the yaw angle on hydrodynamics and wake flow pattern of ducted turbine were analyzed by computational fluid dynamics(CFD)method based on the tidal current conditions in Zhaitang Island. The results show that the hydrodynamic performance of ducted turbine with different immersion depths and yaw angles show time periodic behavior consistent with the wave frequency. There is a strong transition on flow and a higher-amplitude fluctuation on hydrodyna-mic performance caused by wave-current effect with the decreasing of immersion depth. The average power coefficient and thrust coefficient of ducted turbine decrease gradually with the increasing of yaw angle under wave-current and yaw flow effect. Besides, it will also cause additional periodic fluctuations in hydrodynamic performance during one rotating period of the rotor, and the frequency of the fluctuation is determined by the rotational speed and the number of blades. The fluctuation amplitude increases with the increasing of yaw angle, and the wake structure behind ducted turbine will become quite unstable and complex.
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Received: 03 November 2020
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