An Application of the Localized Finite Element Method to 3-dimensional Free Surface Wave Problems

3차원 자유표면파 문제에서의 국소유한요소법의 응용

In this paper, the localized finite element method(LFEM) is applied to 3-dimensional ship motion problems in water of infinite depth. The LFEM used here is based on the functional constructed by Bai & Yeung(1974). To test the present numerical scheme, a few vertical axisymmetric bodies are treated by general 3-dimensional formulation. The computed results of hydrodynamic coefficients for a few vertical spheroids and vertical circular cylinders show good agreement with results obtained by others. The advantages of the present numerical method compared with the method of integral equation are as follows; (i) The cumbersome existence of irregular frequencies in the method of conventional integral equation is removed. (ii) The final matrix is banded and symmetric and the computation of the matrix elements is comparatively easier, whereas the size of the matrix in the present scheme is much larger. (iii) In the future research, it is possible to accommodate with the nonlinear exact free surface boundary condition in the localized finite element subdomain, whereas the linear solution is assumed in the truncated(far field) subdomain.