유한수심에서의 선박 운동해석을 위한 유한요소해법개발

Abstract

Ship motion in a harbor has a different behavior compared with that in deep sea in general. This difference results from the effect of shallow water depth and harbor geometry such as quay wall. The excessive motion of a container ship moored in a harbor influences on the efficiency of loading performance of gantry crane. To investigate a ship motion in a harbor, an efficient numerical method which can consider the effect of sea-bottom topography as well as complex harbor geometry is required. In this paper, a numerical method using finite element method is developed for three-dimensional ship motion problem with a finite water depth in frequency domain. For the computational efficiency in huge matrix manipulation, Bi-Conjugate Gradient (BCG) method is used to solve final complex symmetric matrix. Mixed element such as tetrahedral element and hexahedral element is adopted for the flexibility of grid system. Developed numerical method is applied to two different cases; Floating rectangular barge located near quay wall and S175 container ship in a finite water depth. For the validation of present method, numerical results are compared with those of boundary element method based on wave Green function.