| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系 === 104 === Hyperpycnal flows (or turbidity currents) are important in oceanic transportation, they carry subaerial turbidites into deep sea area and are also essential to submarine canyon development. Although submarine canyons are ubiquitous, the mechanism of canyons evolution is still a matter of debate. In this study, one dimensional micro-scale tank experiment was conducted to investigate the mechanism by which turbidity currents erode and incise the canyon floors. During the process of the experiment, we use time-lapse photograph to record the overall process of canyons’ evolution, and analyze them by image analysis methods to obtain quantitative topographical data. The experiment results indicate that submarine canyons will reach stable slope eventually in each evolution period with the growing of continental slope. The result also shows highly self-similarity in these cross sections by dimensional analysis. Furthermore, by tracing the tine series of bedform profiles we observe the correlation between the scours' wavelength and flow rate. Base on this finding, we calculate the Densimetric Froude number of turbidity currents along the section and manifest them to be supercritical flow. Among such analysis above, we hope that this study can facilitate the understanding of submarine canyons and arise more attention toward morphological study.
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