| URN | etd-0714115-133307 | Statistics | This thesis had been viewed 392 times. Download 4 times. |
| Author | Shang-Yu Jhang | ||
| Author's Email Address | No Public. | ||
| Department | Department of construction & spatial design | ||
| Year | 2014 | Semester | 2 |
| Degree | Master | Type of Document | Master's Thesis |
| Language | zh-TW.Big5 Chinese | Page Count | 50 |
| Title | Experimental Study on Flow Visualization and the Generation of Solitary wave by landslides | ||
| Keyword | |||
| Abstract | The researchers of the present study adopted various landslide conditions to determine the optimal solitary waveform, which was then used in wave generation. The ink flow method was adopted to examine the effects of waveform changes of solitary wave on water surface as well as the wave flow changes when the solitary wave passes through a submerged breakwater. Subsequently, the researchers screened various conditions to identify the optimal waveform that best resembled solitary waveforms. These conditions included the position, height and weight of the object. The waveform that best resembled the theoretical values was extracted from a condition and incorporated into the next condition. This layered screening method was repeated to determine the optimal waveform. The screening results for the position conditions revealed that the optimal landslide length was L=1.8 m. This value was incorporated into the height condition to reveal an optimal landslide height of H=22.5 cm. These two values were incorporated into the weight condition to reveal an optimal weight of W=60 kg. Finally, the optimal waveform for solitary waves was determined using the parameters L=1.8 m, H=22.5 cm, and W=60 kg. The researchers applied the solitary waveform generated using the aforementioned process to two sinusoidal submerged breakwater systems (gradational and composite) and conducted a series of tests using the ink flow method. By observing the flow paths of the ink, the researchers were able to determine the state of the solitary wave when passing through the two systems. Compared to the composite system, ink flow results showed that vortex occurred less in the gradational system. This was possibly because vortex typically occurs on the rear end of submerged breakwaters when waves and currents collide with the breakwater. The gradational system manifested insufficient space for vortex to occur, resulting in vortex occurring only once the solitary wave had passed through the submerged breakwater. By contrast, the composite system provided sufficient space between each set of submerged breakwaters for vortex to completely form. The image extractions of the ink flow conditions showed that when the solitary wave passed through the composite system, the ink did not flow to the following submerged breakwater section due to the dissipation of wave and current strength. These results were significantly different to those of the gradational system, where most of the ink was carried directly to the rear end of the breakwater structure. Moreover, the researchers were able to clearly determine the retention performance of the submerged breakwaters when the solitary wave passed through the two systems by examining the scale of the vortex and the fluid dynamics of the ink. Observations showed that the retention capability of the composite system was far better than that of the gradational system. As the solitary wave passed through the gradational system, the ink was carried vertically downward, and only a small portion generated small vortex as a result of circumfluence. By contrast, circumfluence was exhibited between submerged breakwaters in the composite system, which caused much larger vortex. These results are also associated to the aforementioned discussion on space. According to the flow field diagrams, the dissipation of energy exhibited when the solitary wave passed through the composite system clearly indicates that the gradational system posed limited influence on solitary waves, and that the influence of the composite system can be greatly elevated by increasing the number of submerged breakwaters. |
||
| Advisor Committee | |||
| Files | indicate access worldwide | ||
| Date of Defense | 2015-07-06 | Date of Submission | 2015-07-15 |