Abstract
The previous report presented an elementary description of a cross-flow turbine for a tidal or a wave power plant. In order for the turbine to rotate in the same direction in reciprocating flows, this turbine performance is influenced by the symmetrical nozzle shapes around its axis. Then we investigate the relation between the turbine performance and the changes in the flow passage area. It is desirable that the changes in the flow passage area be smooth and the diffuser angle be small. Therefore, the separation in the diffuser become smaller and the turbine performance is improved.
