Assessment of blade element actuator disk method for simulations of ducted tidal turbines

The blade element actuator disk (BEAD) method, due to its relatively low computational cost, is a good choice for in-situ simulations of tidal turbines. In this work, the performance of the BEAD method for simulating ducted tidal turbines is investigated and its advantages and disadvantages, in comparison with the actuator line (AL) method, are discussed. The assessment is performed by simulating two ducted tidal turbines using a GPU-based CFD solver. The first turbine, the Clean Current ducted tidal turbine, has a tip clearance equal to 1% of its span. This turbine is simulated at different tip speed ratios (TSRs) and predicted normalized power and thrust coefficients are compared with experiment and the AL method. At TSR = 5, the difference between normalized power and thrust coefficients obtained from the BEAD method and the experiment are 3.2% and 0.8%, respectively. The second turbine is the turbine studied by Cresswell et al., has a relatively high tip clearance of 5% of its span, and is simulated at its design TSR. Contrary to the Clean Current turbine, the BEAD method does not perform as well for this turbine, where the difference between the power coefficients obtained from the BEAD method and experiment is 18.2%.