Hydrodynamic Analysis of a Fixed Offshore Wind Tower Using ANSYS Aqwa

Abstract

AbstractThis study deals with the hydrodynamic analysis of a fixed type offshore wind tower (OWT) using ANSYS Aqwa and is performed to identify the best performing model that has the robustness and capability to support the loads in operating as well as storm conditions. The dynamic behaviour of the structure under wave, wind and current loading is reported for the site conditions in Gulf of Kutch in the state of Gujarat, India. The study is focused on investigation of a jacket structure called modified twisted jacket (MJ) structure (Chen, I. W., Wong, B. L., Lin, Y. H., Chau, S. W., Huang, H. H.: Design and analysis of jacket substructures for offshore wind turbines. energies. 9, 264–278, 2016). The numerical investigations of four different models of varying geometric configurations MJ0, MJ30, MJ60 and MJ90 are considered. For validation purpose, static analysis of two models (MJ0 and MJ60) is performed using ANSYS, and results are found to be in agreement with the published literature. The dynamic analysis performed on the models includes free vibration, hydrodynamic and fatigue analysis. From free vibration analysis, MJ90 has the least natural time period compared to other models, and it lies away from the wave period of the site. Under hydrodynamic analysis, MJ90 has shown best performance. The maximum body forces and moments obtained at the centre of gravity of the structure from hydrodynamic analysis were taken to static structural in ANSYS to predict the design life of the structures. The MJ90 model shows the robustness with very high design life.KeywordsANSYS AqwaHydrodynamic analysisJacket structureOffshore wind tower