Two-dimensional scattering from an inhomogeneous dielectric cylinder embedded in a stratified medium: case of TM polarization

1994 ◽  
Vol 42 (1) ◽  
pp. 16-21 ◽  
Author(s):  
N.P. Zhuck ◽  
A.G. Yarovoy
Keyword(s):  
Stratified Medium ◽  
Dielectric Cylinder ◽  
Two Dimensional ◽  
Inhomogeneous Dielectric

scholarly journals Embedding Approach to Modeling Electromagnetic Fields in a Complex Two-Dimensional Environment

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Anton Tijhuis ◽  
Ann Franchois ◽  
Jean-Michel Geffrin
Keyword(s):  
Spectral Representation ◽  
Numerical Procedure ◽  
Problem Solution ◽  
Dielectric Cylinder ◽  
Two Dimensional ◽  
Efficient Computation ◽  
Extrapolation Procedure ◽  
Cpu Time ◽  
Inhomogeneous Dielectric ◽  
Homogeneous Environment

An approach is presented to combine the response of a two-dimensionally inhomogeneous dielectric object in a homogeneous environment with that of an empty inhomogeneous environment. This allows an efficient computation of the scattering behavior of the dielectric cylinder with the aid of the CGFFT method and a dedicated extrapolation procedure. Since a circular observation contour is adopted, an angular spectral representation can be employed for the embedding. Implementation details are discussed for the case of a closed 434 MHz microwave scanner, and the accuracy and efficiency of all steps in the numerical procedure are investigated. Guidelines are proposed for choosing computational parameters such as truncation limits and tolerances. We show that the embedding approach does not increase the CPU time with respect to the forward problem solution in a homogeneous environment, if only the fields on the observation contour are computed, and that it leads to a relatively small increase when the fields on the mesh are computed as well.

Mixed region collapse with internal wave generation in a density-stratified medium

1969 ◽  
Vol 35 (3) ◽  
pp. 531-544 ◽  
Author(s):  
Jin Wu
Keyword(s):  
Wave Pattern ◽  
Stratified Medium ◽  
Two Dimensional ◽  
Viscous Effects ◽  
Gravitational Effects ◽  
High Frequencies ◽  
Three Stages ◽  
Internal Wave Generation ◽  
Two Stages ◽  
Time Decrease

An experiment has been conducted modelling a two-dimensional mixed region collapsing in a continuously density-stratified medium. The process of collapse can be divided into three stages. Empirical formulae have been derived to describe the process of the first two stages, during which gravitational effects determine the modelling criterion. The collapse in the final stage is complicated by viscous effects; a ratio between the Froude number and the Reynolds number seems to provide a probable modification of the time scale.The pattern of internal waves generated by the initial impulsive collapse of this mixed region can be represented by moving rays connecting either wave crests or troughs. These rays move away from the collapse centre and at the same time decrease their slopes from the horizontal. A simpler steady-state wave pattern generated by an oscillating plunger has also been studied. Taken together, these experimental results are interpreted to show that the energy density of the collapse is skewed toward high frequencies and is peaked at 8/10 of the Brunt-Väisälä frequency of the medium.

Sign in / Sign up

Export Citation Format

Share Document