碩士 / 國立臺灣大學 / 工程科學及海洋工程學研究所 / 96 / The numerical simulation and model test of the dynamic motion of an Underwater Glider were studied in the paper.
The operational principle of the Underwater Gliders is to use the so called Buoyancy Engine, to control inflow and outflow of the water volume inside its water chamber, i.e. to change the buoyancy (or weight )of the glider, so that the glider would move forward during its up-lift and down-sink motion.
The numerical simulations were carried by O.D.E. solver in Matlab. Base on the Runge-Kutta time integration this solver calculate the dynamic motion of the glider, so that the gliding velocity, angle of attack and the trajectory of the glider can be obtained simultaneously. A GUI (Graphical User Interfaces) program is also written so that the design parameters and the initial conditions of the simulation can be easily changed for the program users.
In this simulation, empirical hydrodynamic coefficients were estimated according to the Datacom database.
For the model test, a P.V.C cylindrical glider body with rectangular thin wing was made firstly. A pressure type buoyancy engine was designed inside the glider body. It consists of a steel bottle with highly compressed air inside, electromagnetic valves and piping system. The working principle of this buoyancy engine is to use the valves to control the inflow and outflow of the compressed air in the elastic bladder inside the water chamber. So that the glider would perform lift-sink motion due to the effect of buoyancy force changed.
The test is conducted in the water tank in the Department of Engineering Science and Ocean Engineering of NTU. Two underwater CCD cameras were use to record the image of the glider motion, with the help of the coordinate line printed on the tank wall, its trajectory can be obtained.
The test results are:
The horizontal range of a cycle is 9m, the depth of a cycle is 3m, the pitch angle (when sinking) is 23.75 degrees, the pitch angle (when lifting) is 34.06 degrees.
The numerical simulations results are :
The horizontal range of a cycle is 10.2m, the depth of a cycle is 3.2m, the pitch angle (when sinking) is 23.3 degrees, the pitch angle (when lifting) is 33.04 degrees.
| Identifer | oai:union.ndltd.org:TW/096NTU05345021 |
| Date | January 2008 |
| Creators | Tso-Cheng Hsiao, 蕭左政 |
| Contributors | 謝傳璋 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 52 |
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