Generalised Boundary Element Method to Analyse Marine Current Turbines Hydrodynamics Including Flow Separation and Stall

A computational model for the hydrodynamic analysis of horizontal axis marine current turbines is presented. The methodology is an original extension of a Boundary Integral Equation Method (BIEM) for inviscid flows to describe the flow features that characterize hydrokinetic turbines. To this purpose, semi-analytical trailing wake and viscous-flow correction models are introduced. A validation study is performed by comparing hydrodynamic performance predictions with experimental data on a model turbine with variable pitch blades. The capability of the proposed methodology to correctly describe turbine thrust and power over a full range of operating conditions is demonstrated. Viscosity effects associated to blade flow separation and stall are predicted and thrust and power are comparable with results of blade element methods that are largely used in the design of marine current turbines.