Infinite Elements for Three-Dimensional Fluid-Structure Interaction Problems
Abstract
This report describes a method for using three-dimensional infinite elements to compute acoustic fields in the infinite region containing water that surrounds a submerged structure. In this method, finite elements are used to represent a bounded region that contains the structure and in some cases contains part of the surrounding water. The unbounded region that surrounds the bounded region represented by finite elements and that contains the remainder of the water is represented with infinite elements. The infinite elements implement the added mass approximation to the Helmholtz equation. Several other methods are available for modeling the effects of the surrounding water. For the added mass approximation, an alternative to using infinite elements is to model parts of the surrounding water with several layers of finite elements. To determine whether the method using infinite elements gives an advantage, the efficiency of that method is compared with the efficiency of the alternative method. The relative efficiencies are determined by comparing, for each method, the effort to construct the model and the accuracy of the solutions obtained. Evaluation of the infinite elements shows that they produce accurate results especially if they are used over a layer of finite fluid elements. However, when solutions obtained using infinite elements are compared with solutions obtained using only finite elements, it is seen that, for added mass problems, infinite elements do not offer a significant advantage over finite elements. Infinite elements are expected to provide a greater advantage when used to solve the Helmholtz equation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1987
- Accession Number
- ADA189462
Entities
People
- Erwin A. Schroeder