An Inverse Parameter Problem with Generalized Impedance Boundary Condition for Two-Dimensional Linear Viscoelasticity

2021 ◽  
Vol 81 (4) ◽  
pp. 1668-1690
Author(s):  
Olha Ivanyshyn Yaman ◽  
Frédérique Le Louër
Keyword(s):  
Boundary Condition ◽  
Linear Viscoelasticity ◽  
Impedance Boundary Condition ◽  
Two Dimensional ◽  
Impedance Boundary ◽  
Parameter Problem

scholarly journals A High-Order Compact 2D FDFD Method for Waveguides

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Gang Zheng ◽  
Bing-Zhong Wang
Keyword(s):  
Boundary Condition ◽  
Finite Difference ◽  
Surface Impedance ◽  
Transverse Field ◽  
High Order ◽  
Impedance Boundary Condition ◽  
Two Dimensional ◽  
Dispersion Characteristics ◽  
Impedance Boundary ◽  
Numerical Examples

A high-order compact two-dimensional finite-difference frequency-domain (2D FDFD) method is proposed for the analysis of the dispersion characteristics of waveguides. A surface impedance boundary condition (SIBC) for the high-order compact 2D FDFD method is also given to model lossy metal waveguides. Four transverse field components are involved in the final eigenequation. Numerical examples are given, which show that this high-order compact 2D FDFD method is more efficient than the low-order compact 2D FDFD method and has a less storage cost.

A METHOD FOR THE TREATMENT OF A SLOPING SEA BOTTOM IN THE PARABOLIC APPROXIMATION

1996 ◽  
Vol 04 (01) ◽  
pp. 89-100 ◽  
Author(s):  
J. S. PAPADAKIS ◽  
B. PELLONI
Keyword(s):  
Boundary Condition ◽  
Helmholtz Equation ◽  
Pressure Field ◽  
Impedance Boundary Condition ◽  
Parabolic Approximation ◽  
Impedance Boundary ◽  
Local Boundary ◽  
Sea Bottom ◽  
Local Boundary Condition ◽  
Non Local

The impedance boundary condition for the parabolic approximation is derived in the case of a sea bottom profile sloping at a constant angle, as a non-local boundary condition imposed exactly at the interface. This condition is integrated into the IFD code for the numerical computation of the pressure field and implemented to test its accuracy in some benchmark cases, for which the backscattered field is negligible. It is shown that by avoiding the sloping interface, the results obtained are closer to the benchmark results given by normal mode codes solving the full Helmholtz equation, such as the 2-way COUPLE code, than those of the standard IFD or other 1-way codes, at least for problems that do not have significant backscattering effects.

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