Abstract
Most simulations involving metamaterials often require complex physics to be solved through refined meshing grids. However, it can prove challenging to simulate the effect of local physical conditions created by said metamaterials into much wider computing sceneries due to the increased meshing load. We thus present in this work a framework for simulating complex structures with detailed geometries, such as metamaterials, into large Finite-Difference Time-Domain (FDTD) computing environments by reducing them to their equivalent surface impedance represented by a parallel-series RLC circuit. This reduction helps to simplify the physics involved as well as drastically reducing the meshing load of the model and the implicit calculation time. Here, an emphasis is made on scattering comparisons between an acoustic metamaterial and its equivalent surface impedance through analytical and numerical methods. Additionally, the problem of fitting RLC parameters to complex impedance data obtained from transfer matrix models is herein solved using a novel approach based on zero crossings of admittance phase derivatives. Despite the simplification process, the proposed framework achieves good overall results with respect to the original acoustic scatterer while ensuring relatively short simulation times over a vast range of frequencies.
Highlights
Over recent decades, there has been a lot of progress regarding numerical simulation techniques in the field of wave physics, mostly benefiting from modern hardware and software improvements
We propose an acoustic scattering study where compact metamaterialinspired acoustic diffusers, called metadiffusers [30,31,32], are considered too complex to simulate directly in a 3D Finite-Difference Time-Domain (FDTD) scheme, and decide to evaluate the computational and scattering impact of RLC impedance boundary conditions (IBC) on the diffuse field of a larger space in which they could be installed, such as an orchestra pit
This is why the aforementioned equivalent surface impedance as a fitted RLC circuit within an FDTD model is proposed to bypass the numerical limitations of large-scale multiphysics simulations, while faithfully reproducing the intended scattering of the metadiffuser embedded in a larger scene
Summary
There has been a lot of progress regarding numerical simulation techniques in the field of wave physics, mostly benefiting from modern hardware and software improvements. In the case where the volume of the simulated scenery happens to be very large compared to the metamaterial meshing dimensions, traditional modelling strategies could prove non-viable within realistic means, likely resulting in immense computational times and memory requirements This calls for alternative strategies in modelling local wave interactions at boundaries and their respective propagation behaviour in much larger spaces within more reasonable computational means. The concept of impedance [10] has helped in establishing a strategy for approximating the physical conditions created by the geometry of an object by a set of impedance boundary conditions (IBC) [11] Many of such investigations began to appear in numerical applications linked to electro-magnetic [12,13], heating [14], and acoustic [15] problems to reduce the computational load, so in the early years of scientific computer simulations.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
