We report upon an experimental study of internal gravity waves generated
by the large-amplitude vertical oscillations of a circular cylinder
in uniformly stratified fluid. Quantitative
measurements are performed using a modified synthetic schlieren technique
for strongly stratified solutions of NaCl or NaI.
Oscillatory turbulent patches that develop around the cylinder
are found to be the primary source of the observed quasi-monochromatic
wave beams whose characteristics differ from theoretical predictions and
experimental investigations of waves generated by small-amplitude
cylinder oscillations. Over long times the waves break down into
turbulence that is examined quantitatively through conductivity
probe measurements and qualitatively through unprocessed synthetic
schlieren images. Based on observations of the location of wave
breakdown we determine that the likely mechanism for breakdown is through
parametric subharmonic instability. This conclusion is supported
by fully nonlinear numerical simulations of the evolution of a
temporally monochromatic internal wave beam.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/835 |
| Date | 06 1900 |
| Creators | Clark, Heather A |
| Contributors | Sutherland, Bruce (Physics & Earth and Atmospheric Sciences), Flynn, Morris (Mechanical Engineering), Heimpel, Moritz (Physics), Swaters, Gordon (Mathematical and Statistical Sciences) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 1068198 bytes, application/pdf |
| Relation | Clark, H. A. and B. R. Sutherland (2009). Schlieren measurements of internal waves in non-Boussinesq fluids. Experiments in Fluids 47(2), 183-194. |
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