Optimization of Transient Design Waves In Random Sea

Abstract

Transient design waves in random sea are optimized by a Sequential Quadratic Programming method. The procedure is based on the linear wave superposition model which allows an exact representation of the wave train in frequency domain. For a given design variance spectrum, the desired characteristics of the design wave regime regarding wave height and crest structure are generated by optimizing an initially random phase spectrum. The solution depends on the initial phase values resulting in different wave regimes for the same problem definition. The analysis of the linear wave evolution is expanded to a fully nonlinear simulation using the finite element method based on potential flow theory. Results are shown for a high transient design wave within a tailored group of three successive waves embedded in random sea which is described by the finite depth TMA spectrum. The maximum wave height of the transient design wave is twice the significant wave height.