Two researchers from Ecole Centrale de Nantes (ECN) working on FLOATECH, participated in the 18th Journées de l'Hydrodynamique in November 2022. Their presentation is now available on the conference proceedings.
This paper has been written by Ruddy Kurnia and Guillaume Ducrozet from the Hydrodynamics, Energetics and Atmospheric Environment Research Laboratory (LHEEA) of ECN. The paper entitled "Computation of Second-Order Wave Loads on Floating Offshore Wind Turbine Platforms in Bi-Chromatic Bi-Directional Waves Using Open-Source Potential Flow Solver NEMOH" is available in open access on the project website and on Zenodo.
All the publications from this conference are accessible through their website: 18èmes Journées de l'Hydrodynamique - Sciencesconf.org
Summary:
Second-order wave loads on a floating structure may excite resonance phenomena, such as slow-drift or springing, at the natural frequencies of the floating structure. Therefore, taking into account the response of a floating offshore wind turbine (FOWT) platform under non-linear wave loads is of paramount importance for its design. This paper presents computation results of the quadratic transfer functions (QTFs) for sum- and difference-frequencies wave loads on FOWT platforms using open-source potential flow, boundary element solver NEMOH. The QTFs are composed of quadratic terms and second-order potential terms. The quadratic terms are computed based on the near-field formulation, while the computation of potential terms is based on the indirect method that uses the Green-formulation and an assisting function, which is the normalized radiation potential. In this paper, we show the NEMOH QTFs computation on two FOWT platforms, the OC4-DeepCwind submersible platform and the SOFTWIND spar-type platform. The results are compared with the reference commercial software HYDROSTAR. Excellent agreement between the two QTFs results is achieved. The focus is put on bi-directional difference-frequency of surge, heave, and pitch QTFs and on sum-frequency full QTFs.
References:
Authors: R. Kurnia and G. Ducrozet - LHEEA, Ecole Centrale de Nantes
Conference: 18èmes Journées de l'Hydrodynamique