Hydrodynamic response of an integrated structure with monopile-type offshore wind turbine and UHMWPE cage affected by wave and current

Abstract

The comprehensive development and utilization of marine energies and resources have been concerned in recent years. A novel integrated structure including the offshore wind turbine (OWT) and aquaculture cage has been proposed to utilize the advantage of each part. In this study, a combined wave-current generation module is self-developed and implemented in the open-source module ‘waves2Foam’. Then, the hydrodynamic characteristics of the integrated structure under wave-current loading are researched based on the open-source toolbox ‘OpenFOAM’, by modeling the ultra-high molecular weight polyethylene (UHMWPE) aquaculture cage as the porous media model. It is noted that the influence of the UHMWPE cage on the hydrodynamic behaviors of the monopile is enlarged under combined wave-current loading, compared to the case under only wave loading. For example, when the wave with 1.44 m wave height and 5.054 s period is applied, the maximum changes for wave run-up and pressure on the monopile with cage are 7.55 % and 7.18 %, respectively, relative to that without cage, while these values become 17.94 % and 18.45 %, respectively, after additionally imposing the current with 0.4 m/s velocity. The present study guides into the design and safety assessment of the integrated structure in the engineering of exploiting marine resources.