Foundation-based flow acceleration structures for marine current energy converters

This study presents a preliminary experimental study investigating the potential benefits of foundation-based flow acceleration structures for marine current energy converters (MCECs). Such structures would provide multiple benefits, including; increased device power output, increased foundation footprint and scour protection. Two phases of experimental testing have been conducted. The first series of tests investigated the flow acceleration caused by a ramp foundation without the presence of a MCEC. They were scaled from a shallow tidal flow site and provide evidence that these structures could give power benefits of 12-25% depending on ramp size and flow depth. An optimum ramp size was established based on the suitability of the vertical velocity profiles for energy extraction. The second phase of testing modelled a commercial marine current energy convertor with a gravity-based ramp foundation. The device was modelled using actuator plates to represent the interaction between the device and the surrounding flow field. A proposed single-operation installation method using a concrete ramp foundation is proposed and preliminary stability calculations are presented.