Numerical Modelling of Fluid-structure Interactions for Floating Wind Turbine Foundations

摘要

The aim of this study is to model the interactions between fluids andsolids using fully nonlinear models. Non-linearity is important in thecontext of floating wind turbines, for example, to model breakingwaves impacting on the structure and the effect of the solid’s elasticity.In this work, the fluid- and solid-dynamics equations are solved usingseparate finite-element models, which are coupled at every time step.This enables the mutual interactions between fluids and moving solidsto be modelled. Importantly, the coupling algorithm ensures that theaction-reaction principle is satisfied at a discrete level, independently ofthe order of representation of the discrete fields in each model. To theauthors’ knowledge, the present algorithm is novel in that it cansimultaneously handle (ⅰ) non-matching fluid and solid meshes, (ⅱ)different polynomial orders of the basis functions on each mesh, and(ⅲ) different fluid and solid time steps. Results are shown for: (ⅰ) abottom-mounted pile subjected to small-amplitude waves in anumerical wave tank, and (ⅱ) a truncated pile floating at an interfacebetween air and water.