In a paper presented at OMA 2001, an extension of the panel code WAMIT was described where the surface geometry of the structure is represented explicitly and the solution for the velocity potential is approximated by higher-order B-splines. This permits an exact representation of the geometry in many applications, and avoids the effort and approximations inherent in preparing traditional low-order panel inputs. However the algorithms for the explicit geometry definition must be coded in special ad hoc subroutines for each type of structure. In the present paper we describe recent work to integrate the programs MultiSurf and WAMIT, in a manner which circumvents the need for special subroutines. In most practical cases this leads to a substantial reduction of the work required to perform computations of wave effects on structures. MultiSurf is a CAD program which enables users to define surface geometry with a high degree of accuracy, efficiency, and generality. It has been used extensively to develop low-order panel input files for ships and offshore structures, as well as for a variety of other marine design applications. The fundamental approach is to represent each part of the surface which is smooth and continuous by a parametric surface ‘patch’, using appropriate surface constructions which allow these patches to be joined robustly. The kernel of MultiSurf, known as RGKernel, includes the necessary code to evaluate surface locations and derivatives. A close integration of MultiSurf and WAMIT has been achieved by linking RGKernel with WAMIT, so that the same geometry can be reproduced during the hydrodynamic analysis. This integration makes it possible for users to define the geometry of structures interactively in MultiSurf, and to transfer this representation to WAMIT without significant extra effort. Thus the hydrodynamic analysis can be performed with exact or highly accurate representations of the geometry, and with the increased accuracy and efficiency inherent in the higher-order solution based on B-spline representation of the potential. After a brief explanation of the methodology, illustrative results are described for several examples. Comparisons are made of the accuracy, efficiency and workload, relative to the conventional use of low-order panels.
Skip Nav Destination
ASME 2002 21st International Conference on Offshore Mechanics and Arctic Engineering
June 23–28, 2002
Oslo, Norway
Conference Sponsors:
- Ocean, Offshore, and Arctic Engineering Division
ISBN:
0-7918-3611-8
PROCEEDINGS PAPER
Integration of Geometry Definition and Wave Analysis Software
J. S. Letcher, Jr.,
J. S. Letcher, Jr.
AeroHydro, Inc., Southwest Harbor, ME
Search for other works by this author on:
R. G. Mark, II,
R. G. Mark, II
AeroHydro, Inc., Southwest Harbor, ME
Search for other works by this author on:
J. N. Newman,
J. N. Newman
Massachusetts Institute of Technology, Cambridge, MA
Search for other works by this author on:
D. M. Shook,
D. M. Shook
AeroHydro, Inc., Southwest Harbor, ME
Search for other works by this author on:
E. Stanley
E. Stanley
AeroHydro, Inc., Southwest Harbor, ME
Search for other works by this author on:
C.-H. Lee
WAMIT, Inc., Chestnut Hill, MA
J. S. Letcher, Jr.
AeroHydro, Inc., Southwest Harbor, ME
R. G. Mark, II
AeroHydro, Inc., Southwest Harbor, ME
J. N. Newman
Massachusetts Institute of Technology, Cambridge, MA
D. M. Shook
AeroHydro, Inc., Southwest Harbor, ME
E. Stanley
AeroHydro, Inc., Southwest Harbor, ME
Paper No:
OMAE2002-28465, pp. 721-733; 13 pages
Published Online:
February 24, 2009
Citation
Lee, C, Letcher, JS, Jr., Mark, RG, II, Newman, JN, Shook, DM, & Stanley, E. "Integration of Geometry Definition and Wave Analysis Software." Proceedings of the ASME 2002 21st International Conference on Offshore Mechanics and Arctic Engineering. 21st International Conference on Offshore Mechanics and Arctic Engineering, Volume 1. Oslo, Norway. June 23–28, 2002. pp. 721-733. ASME. https://doi.org/10.1115/OMAE2002-28465
Download citation file:
36
Views
Related Proceedings Papers
Related Articles
Boundary-Element Methods In Offshore Structure Analysis
J. Offshore Mech. Arct. Eng (May,2002)
A Computer-Aided Design Technique for Semi-Automated Infinite Point Coupler Curve Synthesis of Four-Bar Linkages
J. Mech. Des (March,1995)
Contact Prediction Between Moving Objects Bounded by Curved Surfaces
J. Comput. Inf. Sci. Eng (March,2012)
Related Chapters
ISO 19901-1 Petroleum and Natural Gas Industries — Specific Requirements for Offshore Structures — Part 1: Metocean Design and Operating Considerations
Ageing and Life Extension of Offshore Facilities
Exchange Helical Shape from a Mechanical CAD System to a Ship CAD System Based on Shape Approximation
International Conference on Instrumentation, Measurement, Circuits and Systems (ICIMCS 2011)
On the Exact Analysis of Non-Coherent Fault Trees: The ASTRA Package (PSAM-0285)
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM)