Modeling underwater cable structures subject to breaking waves

Motivated by the design of a protective anti-shark cable net enclosure located in heavy surf on La Réunion, France, this paper presents a modeling technique for underwater cable structures subject to breaking wave action. Such modeling capability is not offered in leading commercial software. Forces on underwater cable structures are frequently modeled using the well-established Morison equation. These forces are functions of the fluid velocity and acceleration, which are normally calculated using an appropriate wave theory. Such an approach works well in many applications, but it does not permit the modeling the effects of breaking waves. However, considering the absence of wave impact loads on submerged structures, the Morison equation is still valid provided that a suitable hydrodynamic time history is available. In the presented work, the Morison equation is coupled with a high-resolution breaking wave simulation obtained by solving the full air-water Navier-Stokes equations, creating a time-domain analysis approach suitable for studying underwater cable structures subject to breaking waves. The hydrodynamic model is validated using the software package ProteusDS, and the presented model is used to characterize the mechanical response of a moored cable net. This research is of relevance to the analysis and design of submerged cable structures.