Theoretical Analysis on the Helmholtz Scattering Problem of a Partially Covered Sectorial Channel

• Main Authors: Chien-Chih Liu, 劉建智
• Other Authors: Deng-How Tsaur
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/67224626708544394187

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 95 === Abstract As to the Helmholtz scattering problem of the channel, lots of scholars had applied different numerical methods to these topics. However, very few theoretical solutions are provided to compare with numerical ones. Furthermore, to the author’s knowledge, the related investigations on the scattering problem of a partially covered sectorial channel are also rare. Hence, the main purpose of this thesis is to derive series solutions for the electromagnetic scattering problem of a partially covered sectorial channel through theoretical analysis method. Based on the region-matching technique, the semi-circular and circular-arc auxiliary boundaries are introduced to divide the entire computational region into several sub-regions. In each sub-region the expression of the wave field is obtained by satisfying the governing equation and partial boundary conditions respectively. After imposing the continuity conditions at the auxiliary boundaries and constructing simultaneous equations by means of the moment method, the unknown coefficients can be determined. For the E- and H-polarized plane wave incidence, several graphical results are presented to exhibit the effects of incident angle, central angle of the channel and entrance width on the backscattering width, scattered far-field pattern, and equi-amplitude contour. In conclusion, the proposed series solutions can provide benchmarks for the validation of other numerical codes (e.g., finite difference method, finite element method and boundary element method).