3D Modelling of a tidal turbine - A numerical investigation of wake phenomena

Abstract

A three-dimensional CFD model of a tidal turbine was successfully created. The effect of physical parameters, such as twist axis location and blade trailing edge roundness, were discussed. These were found to have a significant impact on the turbine performance. A mesh convergence study was performed to ensure that wake physics is properly resolved. Likewise, a domain length study ensured a full wake recovery. Model validation was completed wherein the turbine performance was compared to experimental data. The impact of blockage was investigated by increasing the cross-sectional domain size. This exhibited minimal impact on turbine performance but greatly affected wake recovery. It was found that blade tip shed vortices are a major contributor to wake recovery. Blockage impeded this contribution, advecting the wake downstream. A complete wake recovery was modelled for a range of TSRs and a preliminary relation between turbine rotation rate and wake recovery distance was determined.