Posters
Come meet the poster presenters to ask them questions and discuss their work
We would like to invite you to come and see the posters at our upcoming conference. The posters will showcase a diverse range of research topics, and will give delegates an opportunity to engage with the authors and learn more about their work. Whether you are a seasoned researcher or simply curious about the latest developments in your field, we believe that the posters will offer something of interest to everyone. So please join us at the conference and take advantage of this opportunity to learn and engage with your peers in industry and the academic community.
PO166: Accounting for Low-Frequency Motions in Structural Assessment of Floating Offshore Wind Substructures
Imanol Touzon, Technical Pre-Sales Manager, DNV
Abstract
Although floating offshore wind turbines (FOWT) development is in early commercial phases and substructure structural assessment methodology is not fully settled down, there is an increasing tendency to perform finite element (FE) analysis of the substructure in the time domain. Such analyses are based on the coupled or integrated loads analysis (ILA) results, requiring both to be as consistent as possible to ensure accurate results. FOWT systems are typically designed so that their rigid-body natural frequencies lie outside the wave excitation frequency range. However, low-frequency (LF) motions still arise from wind loading and wave drift forces, which must be considered in the ILA to obtain realistic mooring forces. Since all the resulting loads of lines attached to the substructure are to be incorporated into the subsequent structural assessment, these loads must be accurately combined with loads arising from other physical phenomena. In cases where wave diffraction and radiation time-domain pressures are reconstructed based on frequency-domain linear hydrodynamic coefficients, it may be relevant to account for the phase shift associated with LF motions during the reconstruction process. Whilst not including the LF motions phase shift can still be used within early design stages increasing speed, this study investigates the impact of accounting for these corrections on the structural time domain assessment. The analyses are performed for a case study representing the VolturnUS-S floating substructure supporting the IEA 15MW wind turbine. The structural response of a set of nodes is introduced in terms of the influence of LF phase shift correction under various design load cases. Results indicate that incorporating LF phase shifts reveals specific mooring load and pressure combinations that may govern the design as well as improve the structural model balance and, therefore, confidence in its results. These combinations could otherwise be overlooked in structural analyses that omit such considerations.
No recording available for this poster.
