The instability of axial-symmetric gravity-capillary waves generated by a vertically-oscillating sphere

When a floating sphere is forced to oscillate vertically, axial-symmetric outgoing ring waves are generally expected to be produced. Laboratory experiments, however, show that when the oscillation amplitude of the sphere exceeds a threshold value, the axial-symmetric waves abruptly transfigure into asymmetric waves. This problem is related to interfacial instability phenomena widely seen in lab model tests such as sloshing, ship model wakes measurements, etc. Despite its fundamental importance, the mechanism that governs the occurrence of this phenomenon is still unknown. The objective of this thesis is to understand the mechanism of this instability phenomenon using theoretical analysis and direct numerical simulations. We first theoretically show that for an arbitrary three-dimensional body floating in an unbounded free surface, there exists a set of homogeneous solutions at any frequency in the gravity-capillary wave context.

Name thesis:degree_name

Doctoral

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2019

Author dc:creator

• Shen, Meng,Ph. D.Massachusetts Institute of Technology.

Advisor dc:contributor.advisor

• Yuming Liu.

• Mechanical Engineering.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/124031

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/124031