A numerical study on the effect of solidity on the performance of transverse axis crossflow tidal turbines

This paper presents a three-dimensional numerical study employing an actuator line model to investigate the effect of turbine solidity on the performance of a Transverse Axis Crossflow Turbine (TACTs). Transverse Axis Crossflow Turbines have a low rectangular form and are ideally suited to relatively shallow tidal and riverine sites due to their ability to handle bi-directional flow intake. Lift based TACTs are not well understood due to their complex hydrodynamics when the downstream sweep passes through the wake produced by the turbine shaft and the upstream sweep. The blade loading, hydrodynamics and ultimately power produced during the downstream sweep depends on the number of blades and turbine solidity. This numerical study is carried out using OpenFOAM and replicates planned fieldwork where the power and in-service blade loading will be monitored as a function of turbine solidity.