Interference and Transmission of locally forced internal waves in non-uniform stratifications

Several studies have investigated the effect of constructive or destructive interference on the transmission of internal waves that propagate through non-uniform stratifications. Such studies have been performed for internal waves that are spatiotemporally harmonic. To understand the effect of spatiotemporal localization, this thesis presents a theoretical and experimental study of the transmission of two-dimensional internal waves that are generated by a boundary forcing that is localized in both space and time. This is done by considering an idealized problem and applying a weakly viscous semi-analytic linear model to it. After validation with a numerical model, the semi-analytic model allows us to perform parametric studies. Using theoretical studies, we show that localization leads to the disappearance of transmission peaks and troughs that would otherwise be present for a harmonic forcing. The laboratory experiments that we perform provide a clear indication of this physical effect. Based on the group velocity and angle of propagation of the internal waves, a practical criteria that assesses when the transmission peaks or troughs are evident, is obtained. It is found that there is a significant difference in the predicted energy transfer due to a harmonic and non-harmonic forcing which has direct implications to various physical forcings such as a storm over the ocean.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2017

Author dc:creator

• Supekar, Rohit B

Advisor dc:contributor.advisor

• Thomas Peacock.

• 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

http://hdl.handle.net/1721.1/111933

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/111933