An exponential growth in the offshore industry has resulted in a corresponding increase in
demand for quick, accurate, and implementable designs. With the increase in size of the
structure relative to the wave amplitude, analysis should be performed using the diffraction
theory. The steady wave drift force on a submerged body is a second-order quantity. With a
potential flow assumption, the force arises from the diffraction and radiation of the waves
from the interaction with the body. For a fixed body in waves the steady force is
contributed from the wave diffraction effect alone. Numerical solutions for are generally
needed for the computation of the steady drift force on submerged structures. In this study
the steady wave drift forces on several fixed bodies of basic shapes are derived in closed
form. The thesis addresses the steady drift forces on the following basic structures: a box, a
vertical circular cylinder, a submerged horizontal cylinder, a bottom-seated horizontal half
cylinder, a bottom-seated hemisphere, a submerged sphere, and an ellipsoid. The results
developed demonstrate the importance of various independent non-dimensional parameters.
To achieve speed and accuracy of the analytical/numerical solutions for the second order forces on the basic bodies with symmetry has been presented. Mathematical
formulation of the boundary value problem and its second order solution have been
described using the different coordinates depending on the symmetry and nature of the
object. Charts and formulas have been developed to provide solution for the second order
wave forces on different basic structures like cylinder, sphere and ellipsoids. This study is
helpful for a first pass estimate of the steady drift force where the translational and
rotational contributions are neglected. The illustrative examples provide a sense of the
accuracy and an approach to bound the results of complex geometries by approximating
them as simpler geometries.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2922 |
| Date | 15 May 2009 |
| Creators | Gupta, Anupam |
| Contributors | Niedzwecki, John M. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
Page generated in 0.0028 seconds