Prediction Of Extreme Wave Slamming Loads On A Fixed Platform

Design of offshore oil platforms requires accurate prediction of the maximum wave loads due to slamming on horizontal decks. The physical processes that influence the load are the propagation of irregular short-crested wind-driven storm seas, wave breaking, and wave-structure interaction. Furthermore, the ocean is a stochastic environment, so the load and its maximum can be considered as random variables. Ideally, the designer would like to know not only the most probable extreme load, but also the extreme load distribution.In this paper we will use a novel technique to prescribe wave environments that lead to extreme responses so that high-fidelity simulations of the highly-nonlinear process can be investigated in detail. Specifically, the dynamics of the relative motion of the sea surface and the platform will be assumed via the selection of a sea spectrum, and the extreme-value probability distribution function (PDF) will be calculated for a given exposure window. The novel aspect of the work is in the way that a set of deterministic sea environments will be generated that are amenable for simulation with a state-of-the-art computational fluid dynamics (CFD) software. The resulting wave environments will be simulated to estimate the extreme-value PDF.