碩士 / 國立臺灣大學 / 工程科學及海洋工程學研究所 / 103 / The underwater vehicle is a vehicle that could carry human beings or equip instruments to carry out underwater missions. Based on different requirements of the missions, we have to choose appropriate ones for both economics and effectiveness considerations. SONAR(SOund Navigation And Ranging) is an useful technique for surveying sea-bottom topographies. Equipping the transducers with the underwater vehicle could increase the effective depth of SONAR. However, the positioning of the underwater vehicle could affect the direction of acoustic waves. The purpose of this study is to design an underwater vehicle equipped with transducers in order to survey sea-bottom topographies and with high stability at the stable pitch angle. We use CAD software to systematically design a parametric geometry shape and analyze its statical equilibrium. The gravity force depends on the weight distribution. We apply Computational Fluid Dynamics to calculate the hydrodynamic force. In addition, we apply the kinematical equations of rigid body, and substitute the computed hydrodynamic force into the Buoyancy Program developed by the NTU ESOE CAD Lab. Furthermore, we use Euler’s method to iteratively calculate mooring force and the stable pitch angle with different mooring joints or weight distributions and numerically estimate the pitch stiffness of the underwater vehicle. According to this research, if the stable pitch angle equals zero, moving the mooring joint forward could increase the pitch stiffness and the weight distributions would become more flexible. When the mooring joint is fixed, the longitudinal center of gravity has to move forward to maintain a constant stable pitch angle if the mass of underwater vehicle increases, however, the pitch stiffness would decrease.
| Identifer | oai:union.ndltd.org:TW/103NTU05345006 |
| Date | January 2015 |
| Creators | Tzu-Ching Liu, 劉子靖 |
| Contributors | 郭真祥 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 90 |
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