Comparison Of Linear And Nonlinear Mathematical Models For Cables In Simulation Of Mooring Forces On Floating Objects

Abstract

A finite element technique is developed to compare the linear and nonlinear cable
equations used in simulation of mooring forces on floating objects. In this technique, the Navier-
Stokes equations for two interacting, incompressible fluids (air and water) are written and
integrated over an Arbitrary Lagrangian-Eulerian domain. The interface between the air and
water is tracked using a transient advection equation. The physical motions of the floating
objects are handled with automatic mesh-moving schemes. The six degrees of freedom nonlinear
rigid body dynamics equation are coupled with the Navier-Stokes equations to update the
positions of the floating objects. The numerical example includes 3D simulations of buoyancy
effects on a floating object under water constrained with a cable.