An Open-Source Python-Based Boundary-Element Method Code for the Three-Dimensional, Zero-Froude, Infinite-Depth, Water-Wave Diffraction-Radiation Problem

In this paper, a new open-source implementation of the lower-order, 3-D Boundary Element Method(BEM) of solution to the deep-water, zero Froude-number wave-body interaction problem is described. Avalidation case for OMHyD, the new open-source package, is included, where the outputs are compared toresults obtained using the widely used frequency-domain hydrodynamic analysis package ANSYS-AQWA.The theory behind the solution to the diffraction-radiation problem is re-visited using the Green functionmethod. The Hess and Smith panel method is then extended to the case of a floating object using theimage-source to impose the wall condition at the free-surface, and a wavy Green function component toaccount for presence of free-surface waves. An algorithm for computer implementation of the procedure isdeveloped and subsequently implemented in PYTHON. The wavy part of the Green function is determinedusing a verified and published FORTRAN code by Teleste and Noblesse, wrapped for PYTHON using theFortran to Python (F2PY) interface. Results are presented for the various stages of implementationviz. panelling, body in infinite fluid domain, effect of the free-surface, and effect of surface-waves. Thehydrodynamic coefficients obtained from this preliminary frequency-domain analysis are shown to be insatisfactory agreement with ANSYS-AQWA results. Conclusions are drawn based on the performance ofthe code, followed by suggestions for further improvement by including the removal of irregular-frequencies,multi-body interactions, and bottom interference, which are not considered in the present implementation.