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A computationally efficient hybrid 2D–3D subwoofer model
Umeå University, Faculty of Science and Technology, Department of Computing Science. (Design Optimization Group)ORCID iD: 0000-0002-3800-6438
Umeå University, Faculty of Science and Technology, Department of Computing Science.ORCID iD: 0000-0003-0473-3263
Umeå University, Faculty of Science and Technology, Department of Computing Science. The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, Uppsala, Sweden.
Umeå University, Faculty of Science and Technology, Department of Computing Science.
2021 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, article id 255Article in journal (Refereed) Published
Abstract [en]

A subwoofer generates the lowest frequency range in loudspeaker systems. Subwoofers are used in audio systems for live concerts, movie theatres, home theatres, gaming consoles, cars, etc. During the last decades, numerical simulations have emerged as a cost- and time-efficient complement to traditional experiments in the design process of different products. The aim of this study is to reduce the computational time of simulating the average response for a given subwoofer design. To this end, we propose a hybrid 2D–3D model that reduces the computational time significantly compared to a full 3D model. The hybrid model describes the interaction between different subwoofer components as interacting modules whose acoustic properties can partly be pre-computed. This allows us to efficiently compute the performance of different subwoofer design layouts. The results of the hybrid model are validated against both a lumped element model and a full 3D model over a frequency band of interest. The hybrid model is found to be both accurate and computationally efficient.

Place, publisher, year, edition, pages
Nature Publishing Group, 2021. Vol. 11, article id 255
Keywords [en]
Acoustics, Applied Mathematics, Computational Science
National Category
Computational Mathematics
Identifiers
URN: urn:nbn:se:umu:diva-178326DOI: 10.1038/s41598-020-80092-9ISI: 000634380400001Scopus ID: 2-s2.0-85098947980OAI: oai:DiVA.org:umu-178326DiVA, id: diva2:1515491
Funder
eSSENCE - An eScience CollaborationSwedish National Infrastructure for Computing (SNIC)Available from: 2021-01-09 Created: 2021-01-09 Last updated: 2023-09-05Bibliographically approved
In thesis
1. Material distribution-based topology optimization for wave propagation problems
Open this publication in new window or tab >>Material distribution-based topology optimization for wave propagation problems
2022 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Materialdistributionsbaserad topologioptimering för vågutbredningsproblem
Abstract [en]

This thesis employs material distribution-based topology optimization for wave propagation problems. In the material distribution approach, we define a material indicator function that models the presence and absence of material in a design domain. By placing material inside the design domain, the aim is to design a device that maximizes the output power or transmission of the system. The time-harmonic linear wave propagation problem is modeled using the Helmholtz equation. The governing equation is solved using the finite element method, and an artificial boundary condition is used to truncate the domain. Moreover, a gradient-based algorithm, the method of moving asymptotes by Svanberg, is used to solve the optimization problem. An adjoint method efficiently computes the gradients of the objective function with respect to design variables. 

This thesis considers two types of wave propagation problems: acoustic (Papers I-III) and electromagnetic wave propagation (Papers IV-V). In Papers I-II, we consider a bandpass design of a subwoofer. The aim of Paper I is to reduce the computational time required to evaluate the performance of a given subwoofer layout. To accomplish this, we develop a computationally efficient hybrid 2D-3D model. A full 3D model, as well as a lumped model, validate the hybrid model's results. Paper II focuses on optimizing the topology of a subwoofer using the computationally efficient hybrid model from Paper I for single as well multiple frequencies. In Paper III, we design a highly efficient uni-directional linear acoustic waveguide. Moreover, we also challenge the use of the term acoustic diode for such uni-directional linear acoustic waveguides in literature. Paper IV deals with the design of a microwave frequency dividing multiplexer, which splits the incoming signals into two frequency bands and delivers them to their respective output ports. In Paper V, we use the adjoint method to perform the sensitivity analysis of a coupled plasmonic problem where a Helmholtz equation is coupled to the Poisson equation. We validate the sensitivities computed using the adjoint method with the finite difference approach.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2022. p. 36
Series
Report / UMINF, ISSN 0348-0542 ; 22.05
Keywords
topology optimization, material distribution, wave propagation problems, Helmholtz equation, acoustics, electromagnetics, plasmonics
National Category
Computational Mathematics
Identifiers
urn:nbn:se:umu:diva-193444 (URN)978-91-7855-749-3 (ISBN)978-91-7855-750-9 (ISBN)
Public defence
2022-04-28, NAT.D.320, Umeå University, Umeå, 13:15 (English)
Opponent
Supervisors
Available from: 2022-04-07 Created: 2022-04-01 Last updated: 2022-04-04Bibliographically approved

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Bokhari, Ahmad HasnainBerggren, MartinNoreland, DanielWadbro, Eddie

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