大振幅動揺中の二次元浮体に働く非線形流体力

概要

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A numerical method is presented for solving the two-dimensional flow in time domain induced by the motion of a body with a large-amplitude. In this method, a free-surface boundary condition is linearized, but a body boundary condition satisfies the changes of the underwater form of the body. The flow around the body is divided into two parts: a wave field and an impulsive flow. The wave field is induced by the motion of body during previous time step, and is represented by a finite sum of harmonics. The impulsive flow is induced by the impulsive motion of body during the current time step, and it is required that the instantaneous body boundary condition is satisfied at each time step. The body boundary condition based on the stream function is applied to the integral equation to get a good accuracy. By making use of this metod, the hydrodynamic forces acting upon a heaving circular cylinder, a swaying circular cylinder and a rolling rectangular cylinder with a large amplitude are evaluated. The free-surface wave profiles around the bodies are shown schematically. It is also shown that the hydrodynamic coefficients as well as the amplitudes and the phase lags of higher-order hydrodynamic forces agree well with the experimental results.
社団法人日本船舶海洋工学会の論文
1991-03-29