Data analysis of the TetraSpar demonstrator measurements

Abstract

Floating offshore wind turbines can extract energy from deep offshore locations,
typically unfit for fixed bottom designs. The complex interaction between the structural
behavior of the floating offshore wind turbine and the stochastic site conditions, however,
is an active area of research. Characterizing the relationship between the environmental
conditions and loads may help design reduced-order models, surrogate models, and physicsbased engineering models for floating wind turbines. This study uses data from the TetraSpar prototype equipped with a 3.6 MW Siemens Gamesa wind turbine. One-to-one simulations performed using an aero-servo-hydro-elastic software are included for comparison. Various tools, including linear correlation, mutual information, feature ordering using conditional independence, and sensitivity analysis using a data-driven variogram fit, are used for the assessment. This study is also helpful in validating the engineering model for future global sensitivity analysis using elementary effects or Sobol indices that require a rigid sampling of features and can, therefore, only be calculated with simulation tools. We find a good agreement between the experiments and simulations. The 10-min. damage equivalent loads on the tower show a correlation, particularly with the wind speed statistics and the significant wave height.