碩士 / 國立臺灣海洋大學 / 電機工程學系 / 105 / In order to assess the impact of offshore wind farm on marine and aircraft radar systems, it is important to predict the RCS (Radar Cross Section) and the scattering electric field of wind turbines. It was found that the tower scattering constitutes approximately 80% of the turbine, as the blades scattering is approximately 15%. The main purpose of this thesis is to calculate the RCS and the scattering electric field of wind turbine tower and blade quickly and effectively .
The tower is divided into n sections so that each section can be analyzed by the far-field approximation, and the RCS of each section can be evaluated analytically. Adding up all the contributions from each section yields the RCS for the wind turbine tower.
A mesh made of bi-quadratic patches are used to model the blades of wind turbine. The PO(physical optics) approximation is utilized to calculate the far-field scattering electric field of the blades and/or its RCS. In the process of calculating the field, we set up some approximate conditions, so that the surface integral can be simplified into a product of two one-dimensional integrals, which reduces the computational complexity. This approach is very efficient to calculate RCS and the scattering electric field for electrically large wind turbine blades with irregular curvilinear surface. It greatly reduces computing time and memory requirement. If suitable patch size is selected for meshing and the aforementioned approximation approach is adopted, the calculation time can be reduced to a half of that by the commercial software FEKO, and also the required memory is cut down by a half.
Separately calculating the scattered field for the wind tower and blades, we then linearly superimpose both contributions to obtain the total radar echo field from the wind turbine.
| Identifer | oai:union.ndltd.org:TW/105NTOU5442020 |
| Date | January 2016 |
| Creators | wang, Jian-Lin, 王健霖 |
| Contributors | Lin, Jiun-Hwa, 林俊華 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 56 |
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