A time-domain model was developed to predict the fluid/structure
interaction of a three-dimensional deformable body in a fluid domain subject to
long-crested finite amplitude waves. These nonlinear waves induce transient
motion in the body. In turn, the interaction of the body with the waves modifies
the wave field, causing additional motion in the body. A time-domain simulation
was required to describe these nonlinear motions of the body and the wave field.
An implicit three-dimensional time-domain boundary element model of the fluid
domain was developed and then coupled iteratively with a finite element model of
the deformable body.
Large body hydrodynamics and ideal fluid flow are assumed and the
diffraction/radiation problem solved. Either linear waves or finite amplitude
waves can be treated in the model. Thus the full nonlinear kinematic and dynamic
free surface boundary conditions are solved in an iterative fashion. To implicitly
include time in the governing field equations, Volterra's method was used. The
approach is similar to that of the typical boundary element method for a fluid
domain where the boundary element integral is derived from the governing field
equation. The difference is that in Volterra's method the boundary element
integral is derived from the time derivative of the governing field equation. The
transient membrane motions are treated by discretizing the spatial domain with
curved isoparametric elements. Newton-Raphson iterations are used to account for
the geometric nonlinearities and the equations of motion are solved using an
implicit numerical method.
Examples are included to demonstrate the validity of the boundary element
model of the fluid domain. The conditions in a wave channel were numerically
modeled and compared to sinusoidal waves. The interaction of a submerged rigid
horizontal cylinder with water waves was modeled and results compared to
experimental and numerical results. The capability of the model to predict the
interaction of highly deformable bodies and water waves was tested by comparing
the numerical model to large-scale physical model experiment of a membrane
cylinder placed horizontally in a wave channel. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36053 |
| Date | 25 July 1991 |
| Creators | Broderick, Laurie L. |
| Contributors | Leonard, John W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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