Influence of Multidirectional Irregular Wave Sampling to Second-Order Hydroelastic Responses of VLFS

Hydroelasticity theory considering the second-order fluid forces induced by the coupling of first-order wave potentials is introduced briefly in this paper. Based on this theory, four types of multidirectional irregular wave samplings are introduced, the frequency steps Δω of the four samplings are 0.04, 0.04, 0.02 and 0.01 rad/s, and the corresponding numbers of wave components N are 17, 75, 147 and 285 respectively. The result of principal coordinates and displacements of a very large floating structure (VLFS) for the four types of sampling are presented and discussed. The influence of the sampling is analyzed. The conclusions show that the sampling of the multidirectional irregular waves influence the second-order hydroelastic response of the VLFS. The accuracy and the computer time of the calculating with sampling of frequency step Δω = 0.02 rad/s are acceptable.© 2009 ASME