An experimental investigation of blockage in a short fence array of tidal turbines

The impact of array-scale blockage effects on the total power extractable from tidal turbine arrays has been the subject of much recent investigation. This paper summarises the results of a series of physical experiments on short fences of five porous discs to investigate blockage effects in the case of a long cross-stream fence array partially occupying the width of a channel. Disc thrusts are seen to increase as the width of the fence is reduced, which concurs with trends predicted by partial fence theory, although the magnitude of the thrust recorded is less than predicted by theory. Flow wake measurements display a degree of scale separation between device and array wake mixing.