Application and verification of deepwater green function for water waves

An efficient method for the numerical evaluation of the free-surface Green function for deep-water application was presented by Telste & Noblesse (198 6) and again by Ponizy et al (1994). A FORTRAN code was include in their 19 86 paper. The numerical method makes use of known mathematical functions. N umerical values of some of these mathematical functions were depicted, but no verification on the accuracy of the Green function routine in an applica tion was given. The purpose of this paper is to compare their numerical val ues in the near-field and far-field regions with other similar computation for the infinite-depth Green function. The results of the infinite-depth Gr een function are also compared with the results from the finite-depth Green function that is more time consuming. Based on the accuracy of the various methods, the regions of application of the efficient deepwater Green funct ion formulation and the effect of the water depth on the Green function are discussed. Any regions of inaccurate results are noted. Forces on submerge d offshore structures and motions of the floating structures are determined using the lower-order panel method and these different Green function rout ines. The results on the motions of a semisubmersible in various water dept hs are compared and the accuracy of these routines in various regions is sh own. The presented results will help the hydrodynamicist and designer to ev aluate the suitable formulation and its regions of application for the accu rate analysis and design of offshore structures.