Fully non-linear potential flow method for multiple floating bodies in confined waters

Paper in proceeding, 2019

Prediction of ship motions and added resistance in waves using numerical methods has become an important part in the design and optimization of ships. Increasing requirements for improved performance come from several different directions, not least through new regulations and requirements for safety and energy efficiency from the International Maritime Organization (IMO), but also through economic incentives in the global transport system.
One successful type of numerical method is the 3D time-dependent fully non-linear potential flow method. The motivation behind the development of these methods is primarily to find an accurate technique for computing forces and motions in waves without the large computational effort required by its viscous counterparts. In this paper SHIPFLOW MOTIONS, one of such methods, is described along with some newly developed techniques which enable more challenging applications such as ship-to-ship interactions in constrained waters. In particular, the paper describes a flexible adaptive grid refinement technique that allows for an improvement in accuracy or computational speed given a fixed number of panels. The technique is also capable of automatically generating grids for complex geometries including multiple bodies and environment constraints such as shallow water and harbors. The paper describes results of a lightering operation, obtained using this technique.