Ocean waves time-series generation: minimum required artificial wave time-series for wave energy converter analysis

Abstract

Ocean waves are complex, irregular, and random, making it difficult to produce definitive and repetitive time-series that represent oceans worldwide. Researchers have attempted to develop wave spectrum models for different oceans to create reliable wave time series for use in time-domain simulations of marine structures. Accurately estimating wave time-series is especially important in the analysing of wave energy converters (WECs) to assess the applied forces on the device and achieve a reliable estimation of the efficiency of the power take-off apparatus at the design stage. Therefore, there is a need for a set of low- and mid-fidelity tools and models to estimate the relation between the wave spectra discretisation and the correct correspondence exceedance probabilities of the wave time-series. The present study aims to respond to this fundamental necessity with a probabilistic and statistical approach. Initially, the whole logical process of time series generation with fitting risk-level analysis is formulated and interpreted. Then, a relationship between the produced artificial time-series and different probabilities of exceedance is developed. Finally, a logical relationship between the required precision of an artificial ocean time-series and the optimal level of design risk is developed and discussed. The findings provide a framework where generated time-series has a relation with the level of design risk.