A Localized Finite-Element Method for Three Dimensional Ship Motion Problems,
Abstract
An application of the localized finite-element method to a three-dimensional time-harmonic free surface flow in a canal is presented. Boundary conditions on both the free surface and the body are linearized and imposed on their equilibrium positions. By utilizing known set of eigenfunctions, the computation domain is reduced to a very small local domain where an eight-node linear three-dimensional element is used. Proper matching is also imposed between two sets of trial functions on the truncated boundary. To be solved are the problems concerning; (1) six degree-of-freedom radiation and diffraction in three dimensions, (2) two dimensional motion corresponding to the local flow at midship cross-sectional plane, and (3) related eigenvalues. Specifically, two sets of results for two ship locations in a canal are presented. In both cases, the eigenvalues of the local cross-sectional plane are shown to play a significant role in the three-dimensional results. A remarkable similarity between existing forces and moment and the damping coefficients corresponding to the modes of their motions are also observed in the results. The accuracy of the three-dimensional results presented here is also discussed by comparing two sets of eigenvalues computed by using two different sizes of finite elements. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1982
- Accession Number
- ADA115643
Entities
People
- Kwang June Bai