Integrated FEM and CFD Simulation for Offshore Wind Turbine Structural Response

Abstract

This paper implements Finite Element Model (FEM)-enabled computational fluid dynamic (CFD) analysis to enable wind and wave time-history analysis with multiple force-induced soil-structure-interaction. The soil-structure interaction of steel monopile supported 5MW wind turbine has been simulated with two common and applicable soil profiles. Lateral soil springs were used according to the American Petroleum Institute (API) Code for p-y curves, while vertical soil springs were generated according to the t-z and q-z API standards. A modal analysis was performed to verify the joint CFD-FEM exhibited a fundamental frequency in the desired range. A verification of the load applications was completed for maximum force and moment under specific wind and wave loading parameters. Deflection results were generated and compared with reliable results published in past studies. Results reveal that a variation in wind speed has a higher impact on soil structure interaction causing a larger deflection than a variance in the significant wave height. It is also evident that the heterogeneous sand profile has a high enough stiffness to cause fatigue damage during extreme multi-hazard loading. It is anticipated that this proposed modeling technique will provide a basis for more accurate application of multi-wind-wave simulations coupled with soil-monopile-interaction.