This paper describes performances and characteristics of a vertical axis marine turbine (VAT) on which variable-pitch blades are equipped. Then, model experiments in a current channel and CFD calculations were carried out in this study. In the model testing, a variable-pitch type turbine model was used. Accuracy of the CFD computation is validated by comparing with experimental results of torque and number of rotation of the turbine model. The CFD calculation is three-dimensional as well as two-dimensional. The corresponding turbine model has three straight blades, which diameter is 0.3 m. Three kinds of tests were performed for model testing in the channel and CFD calculations as well. They were the starting-driving test, the braking test and the forced-rotation test in currents. The forced-rotation test was performed in still water as well in order to know a simple thrust and to estimate ideal efficiency of the turbine.
Form results of model experiments and numerical experiments, the CFD calculation was satisfactory to estimate performance of the turbine. The starting performance could be definitely improved by applying the variable-pitch system. For driving performance, it was very useful to control the pitch angle a little bit even in very fast velocity currents.