Visualisation of flow conditions inside a shoreline wave power-station

The particle flow inside an oscillating water column type wave power-station varies with time and changes direction. In order to establish flow patterns and energy dissipating mechanisms, and to assess the influence of geometry changes on the hydraulic performance, flow visualisation experiments were conducted on a 1/36 two-dimensional model of the Islay prototype wave power-station. It was found that large vortices develop around the comparatively thin front wall for in- and outflow and that internal sloshing occurs during the inflow period. From the observations it could be deduced that the front lip curvature and thickness have to be increased. Previous suggestions to structure the front wall surface in order to reduce wave loads had to be revised as these obstacles would interfere with the inflow. An internal breaker was observed, indicating that the loads on the back wall might be considerably higher than assumed.