Marine current turbine (MCT) is crucial equipment in ocean energy exploration, whose hydrodynamic performance has a significant effect on efficiency of energy extraction. Due to the existence of friction of seabed, inflow velocity varies with vertical location. In this paper, performances of MCTs in uniform and shear inflow are calculated based on RNAS solver. At first, results in uniform inflow compare with experiment as validation. Then, a truncated method has been brought out and validated to be efficient in prediction performance of MCTs at various water depths. This approach has error within 2% compared with the results under real boundary condition, thus the precise of the approach is validated. Finally, recommendation of immergence of turbines is presented.
Exploration of marine current energy is a promising field in renewable energy industry. Marine current turbines (MCTs), which convert current energy into electricity by rotation of the turbines, are one of the crucial devices. Hydrodynamic performance of MCTs has a crucial effect on the efficiency of the transition. Experimental and numerical methods have been applied for researching the performance of MCTs. Experiments are usually carried out at cavitation tunnels, circulation channels and towing tanks. Test data of a 800mm diameter MCT have been published by Bahaj et al. (2007) (2008) and Batten et al. (2007). For numerical research, Computational Fluid Dynamics (CFD) is effective for simulation of the flow, while Blade Element Momentum Theory (BEMT) is a less time-consuming method that is suitable for preliminary prediction. Much progress has been achieved in research for MCTs designing in recent years (Ahmed, 2012; He, 2013; Yu, 2014; Wang, 2014). Optimizing approaches for hydrofoils and blades are developed to improve efficiency of energy extraction.