Hydrodynamic response of a FOWT semi-submersible under regular waves using CFD: Verification and validation

In this work an extensive verification and validation study is performed to evaluate the accuracy and credibility for CFD simulations of hydrodynamic response of a Floating Offshore Wind Turbine (FOWT) with semisubmersible platform under regular waves. A dynamic mooring model is coupled with the CFD code to accurately simulate the mooring system. The surge, heave and pitch RAOs at wave frequency and double wave frequency, mean surge offset and zero frequency surge QTF of the semi-submersible platform are investigated. The numerical uncertainties of the above metrics are quantified based on three sources - statistical, iterative and discretization uncertainty. Amongst them, the discretization uncertainty is identified as the dominant source of numerical uncertainty. The validation uncertainty is finally estimated combining the numerical, input and experimental uncertainties. Most of the metrics have achieved the validation against the experimental measurement within the validation uncertainty except for the mean surge offset and zero frequency surge QTF. The utilization of the coupled CFD-FEM code is proved to be accurate for simulations of FOWT under regular waves. Guidelines for best-practices of the procedure for verification and validation study of CFD simulations of floating structures under regular waves are also given.

Automated summary

In this work, an extensive verification and validation study is conducted to assess the accuracy and credibility of CFD simulations for the hydrodynamic response of a Floating Offshore Wind Turbine (FOWT) with a semisubmersible platform under regular waves. The study incorporates a dynamic mooring model to accurately simulate the mooring system. Various metrics, including surge, heave, and pitch RAOs, are investigated at different frequencies, and the numerical uncertainties are quantified based on statistical, iterative, and discretization uncertainty sources. The results show that the coupled CFD-FEM code is accurate for simulating FOWT under regular waves, and guidelines for best practices in the verification and validation study of CFD simulations for floating structures under regular waves are provided.