The potential flow initial-boundary value problem describing fluid-structure interaction
with fully nonlinear free surface boundary conditions has been studied using a mixed
Lagrangian-Eulerian formulation. The boundary-value problem has been solved in the physical
domain by means of a Bubnov-Galerkin formulation of the Laplace equation. The initialvalue
problem related to the behavior of some of the moving boundaries has been discretized
using various numerical techniques. Among these is a series of predictor-corrector methods.
These methodologies proved to require considerable numerical smoothing to maintain stability
of the numerical scheme. In turn, dissipation led to inaccuracies in the solution of the
problem. In order to avoid this negative effect, a semi-implicit semi-Lagrangian two-time
level iterative scheme that is almost free from smoothing has been developed.
A Bubnov-Galerkin formulation of an elliptic system for the generation of boundary fitted
curvilinear coordinates has been used. When solved iteratively, this method provides orthogonal
meshes of very good characteristics for both symmetric and non-symmetric domains.
Previous publications concluded that the present system was inadequate for non-symmetric
regions leading to lack of convergence in the iterative process. Solutions described in this
work show that this limitation has been overcome.
Fluid responses to periodic excitation of surface-piercing and submerged bodies have
been calculated. Both linear and nonlinear cases show agreement with published results.
Very low total energy/work error has been obtained which demonstrates accuracy, good
stability and convergence characteristics of the numerical scheme. The impulsive response
of tanks of various shapes has also been simulated. Resulting natural frequencies show good
agreement with available data.
A slender body representation of the flow around a hull advancing with forward speed
in otherwise calm water has also been simulated. Numerical calculations of a number of
quantities of engineering interest are presented for different length Froude numbers. Results
compare favorably with experimental data. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/41452 |
| Date | January 1993 |
| Creators | Allievi, Alejandro |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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