Abstract
Tidal stream turbines (TST) have been identified as a desirable technology for harnessing tidal energy. Measurement and characterisation of wakes are critical for environmental and development reasons. Wake recovery length is an important parameter for appropriate design of arrays, and wakes may result in altered dynamics both within the water column and at the seabed. Laboratory-scale experiments over mobile beds have been conducted to quantify the detailed wake structure and its impact on sediment transport dynamics. A 0.2 m diameter model turbine was installed and a steady current was driven over an artificial sediment bed using recirculating pumps. A Nortek acoustic current-meter Aquadopp was used to measure the three-dimensional mean current with vertical profiles at different locations from the turbine. A three-dimensional Acoustic Ripple Profiler was used to map the bed during the experiments. These measurements provide comprehensive data sets which can be combined to (i) characterise wakes, bed disturbances, and the impact on suspension processes and, (ii) used to inform and validate numerical models.