An Application of Fully Nonlinear Numerical Wave Tank to the Study On Chaotic Roll Motions

TLDR: In this article, a numerical wave tank is applied to the study of chaotic roll motions of a two-dimensional floating body, which is constructed by a time-domain, fully nonlinear simulation method based on potential theory.

Abstract: A numerical wave tank is applied to the study of chaotic roll motions of a two-dimensional floating body. This numerical wave tank is constructed by a time-domain, fully nonlinear simulation method based on potential theory. In this simulation method, boundary value problems both on the velocity potential f and its time derivative ∂f/∂t are solved. The coupling condition between wave and floating body is imposed as the implicit boundary condition of ∂f/∂t on a wet body surface. The radiation condition at the tank ends is satisfied by artificial damping technique. Using this numerical wave tank, the chaotic motions of a 2-D unstable floating body with a small negative GM are simulated in time domain taking fully nonlinear fluidbody interaction into account. The simulated time history, phase plot and Poincare section of roll motions are presented and the dependency of the motion to wave height is discussed. *ISOPE Member. Received March 5, 1998: revised manuscript received by the editors October 2, 1998. The original version (prior to the final revised manuscript) was presented at the Eighth International Offshore and Polar Engineering Conference (ISOPE-98), Montreal, Canada, May 24-29, 1998.