Feasibility studies of a novel spar-type floating wind turbine for moderate water depths: Hydrodynamic perspective with model test

Abstract

Spar-type platforms have been widely applied in ocean engineering and first get commercial applications in the offshore wind industry. The spar-type platform is typically deployed in deep waters whereas shallow and moderate water depths are regarded as more ideal regions for deploying floating wind turbines (FWT). However, the deep draft of spar-type platform limits its use in these regions, encountering great challenges. This paper aims to seek a solution for deploying spar-type FWTs in moderate water depths of about 100 m. To this end, a novel Stepped Short Spar for Shallow water is developed by Shanghai Jiao Tong University (SJTU) with a draft of 50 m, abbreviated as SJTU-S4. Then, a model system is designed and manufactured at a scaling ratio of 1:50. An integrated experimental apparatus is constructed and comprehensive model tests are carried out. The hydrodynamic characteristics of the proposed SJTU-S4 FWT are objectively evaluated referring to those of the typical OC3 Hywind FWT. The model test results indicate that the SJTU-S4 FWT has reasonable hydrodynamic performance in water depth of 100 m. This study suggests that the application of SJTU-S4 FWT concept is feasible and can be an alternative in offshore wind exploitation in moderate water depths.