Review of experimental studies on Transverse Axis Crossflow Turbines

Transverse Axis Crossflow Turbines (TACTs) are a niche subset of tidal turbines. TACTs are not as well understood as the more traditional horizontal axis turbine and associated flow theory which leans heavily on advances in wind energy and marine propulsion. This paper reviews laboratory and field based experimental fluid dynamics work from the perspective of turbine performance. The available literature deviates significantly in perspective and scope since it is found that not all papers declare a full complement of parameters, thereby making it difficult to check or validate the respective results. Therefore, identifying trends amongst the variable and sparse datasets is difficult. None of the papers reviewed cite adherence to the recommended tank testing guidelines. The work reviewed analyses aspects such as mounting supports, solidity, blockage and blade support locations in isolation, but the cumulative impact of these variables is unknown. Arising from the analyses carried out as part of this review, blade loading, solidity and blockage were identified as key parameters and are the subject of planned research. Trends between solidity and blockage with tip speed ratio were identified. This paper contributes to the understanding of TACT performance through the tidal turbine performance curve and highlights the need for comprehensive physical testing and model validation.