A FULLY ADAPTIVE FREE SURFACE DEFINITION ALGORITHM SUITABLE FOR MODELLING UNSTEADY WAVE FLOW AROUND FLOATING STRUCTURES

摘要

The development of a robust computational algorithm suitable for modeling the motion of the three-dimensional interface between air, water and a floating structure is described. The algorithm uses an advanced data structure to define the free surface interface as a series of nodes joined to an arbitrary number of other nodes located on the interface. Each node-node connection is defined uniquely as an edge, and the overall surface as a series of patches constructed from an arbitrary number of edges. Continuity of surface gradient and curvature at each node is determined via an iterative procedure. Once calculated this provides sufficient end conditions to define each edge as a parametric cubic spline and each patch as a combination of 3 and/or 4 edge bi-cubic patches. An identical data structure defines the surface of the floating structure. Nodes at the intersection between the floating structure and free surface are accurately tracked over the actual surface of the structure through knowledge of its local gradient and curvature.