Experimental wave flume study of Savonius-type multiple rotor arrays: Fid-Bau Portal

Experimental wave flume study of Savonius-type multiple rotor arrays

Tutar, Mustafa / Veci, Inaki

An array of horizontal axis Savonius-type three-part rotors, each consisting of three blades, is designed and built in-house to conduct performance analysis experiments for a parallel tandem arrangement in a wave flume at different wave physical and positioning conditions. The experiments are performed at different wave heights, wave periods, and longitudinal spacings between the rotors, and their submergence positions are for a previously adjusted constant water depth. The power output and wave-to-mechanical energy conversion efficiency of the “first rotor,” only in a single- and three-rotor array arrangement, is comparatively studied both qualitatively and quantitatively to determine the optimum centre-to-centre spacing between the rotors as well as the wave physical characteristics at intermediate-to-shallow water depths. It is found that a higher rotational speed can be attained at a higher wave height, centre-to-centre rotor spacing and/or wave period until the water wave overtops or breaks down at larger wave periods. A submergence level that is very close to the water's surface is also found to have a positive influence on the rotor performance, while a positive submergence level has a negative effect. The present study suggests that experimental solutions within the wave-current flume can provide a proper guideline for the performance analysis of such device(s) for further studies of the optimization of the design of Savonius type multi-rotor arrays under different operating conditions, if suitable geometry dimensioning, i.e., scaling issues, submergence positioning, rotor spacing, and physical flow conditions, are provided in accordance with the existing water depth.