Peter Risby AndersenGN Audio A/S · Audio Research
Peter Risby Andersen
PhD
Researcher at GN Jabra
About
22
Publications
5,532
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96
Citations
Citations since 2017
Introduction
Senior Research Scientist at GN Audio. Performing research on gradient-based shape and topology optimization for large-scale vibroacoustic devices.
Additional affiliations
November 2018 - March 2020
October 2018 - October 2019
Publications
Publications (22)
This paper presents a method to perform gradient-based shape optimization to minimize the root mean square deviation of the exterior acoustic sound pressure level distribution in front of an initially spherically shaped loudspeaker. The work includes several examples of how different multi-frequency optimization strategies can affect the final opti...
The increasing interest in miniaturizing acoustic devices has made accurate and efficient models of acoustic viscous and thermal losses progressively more important. This is especially the case in micro-acoustic devices such as hearing aids, condenser microphones and MEMS devices. Using the full linearized Navier Stokes equations to numerically mod...
Shape optimization is a promising tool for improving and guiding the design of computationally large-sized vibro-acoustic devices such as compact loudspeaker systems and hearing aids. Typically, such devices are subject to unwanted structural vibrations that can degrade the acoustic performance, i.e., contributing with destructive and constructive...
Improving the performance of loudspeaker units and cabinet designs traditionally relies on a combination of trial and error, sometimes based on a lumped parameter modelling approach. During the last decades, however, large-scale numerical simulations are playing a growing role as a means of improving performance of complex engineering devices such...
It has been shown in several recent publications that acoustic materials consisting of a combination of resonators tuned to different frequencies can render high absorption coefficient values over an extended frequency range while maintaining compactness. This makes them attractive solutions for applications in which low frequency sound control is...
Improving the design of complex industrial sized vibroacoustic devices is a complicated task. The trend is to miniaturize consumer audio devices, but with the aim of maintaining high audio fidelity. This is for example the case for smart speakers and speakerphones. However, it is difficult to make a loudspeaker that is very compact, lightweight and...
Finite element methods are progressively being utilized to assist in the continuous development of loudspeakers. The core of this paper is the method of lumping certain parts of the finite element model, creating a significant reduction in the model complexity that allows for e.g. faster structural optimization. This is illustrated in the paper wit...
Recent developments within the area of acoustic shape optimization show huge potential for the improvement and design of acoustic devices. So far, acoustic shape optimization has been mostly applied to simplified academic setups. However, its application to industrial sized problems is still limited. In this work, we explore the possibilities of ex...
Finite element methods are progressively being utilized to assist in the continuous development of loudspeakers. The core of this paper is the method of lumping certain parts of the finite element model, creating a significant speedup that allows for structural optimization. This is illustrated in the paper with a loudspeaker example where the elec...
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ABSTRACT
Inverse design is currently applied to obtain unusual acoustical devices based on ordered and non-ordered scatterers. Recently, flat and lenticular acoustic lenses, de-multiplexors, directional sound sources and acoustic cloaks have been designed using a variety of optimization methods like genetic algorithms, simulated an...
Acoustic cloaking is a technique that seeks hiding objects in a sound field by reducing or cancelling their scattered sound pressure. Incident waves are restored to as close as possible their original undisturbed form after hitting the cloaked object. One technique for achieving this goal is the design of additional scatterers around the object, wh...
Acoustic meta-surfaces are periodic structures commonly realised using sub-wavelength sized resonators. One of their possible applications is in noise control where they can be applied to create very compact sound absorbers. Numerical modelling and characterization of meta-surfaces require the inclusion of acoustic viscous and thermal dissipation e...
Since the late 1980s, numerical shape optimization has been applied successfully to improve the design and development of novel acoustic devices. Most often, viscous and thermal dissipation effects are neglected in the optimization process, as this is an acceptable assumption in e.g. room acoustics, etc. However, in many acoustic devices, ranging f...
A range of acoustic engineering problems require the inclusion of viscous and thermal dissipation to be modelled accurately. The dissipative effects are especially relevant when the geometric dimensions of the acoustic domain become small which is the case in acoustic transducers and hearing aids. Computer-based numerical tools such as the Finite E...
In recent years, the boundary element method has shown to be an interesting alternative to the finite element method for modeling of viscous and thermal acoustic losses. Current implementations rely on finite-difference tangential pressure derivatives for the coupling of the fundamental equations, which can be a shortcoming of the method. This fini...
Sound waves in fluids are subject to viscous and thermal losses, which are particularly relevant in the so-called viscous and thermal boundary layers at the boundaries, with thicknesses in the micrometer range at audible frequencies. Small devices such as acoustic transducers or hearing aids must then be modeled with numerical methods that include...
Recent research has shown that the performance of acoustic metamaterials can be greatly influenced by the effects of viscous and thermal dissipation. In the worst case, an isentropic assumption can lead to an undesired performance. To further investigate the impact of losses on novel acoustic devices, an already known acoustic cloak is validated nu...
This work presents an updated overview of numerical
methods including acoustic viscous and thermal losses.
Numerical modelling of viscothermal losses has gradu-
ally become more important due to the general trend
of making acoustic devices smaller. Not including vis-
cothermal acoustic losses in such numerical computations
will therefore lead to in...
In recent years, boundary element method (BEM) and finite element method (FEM) implementations of acoustics in fluids with viscous and thermal losses have been developed. They are based on the linearized Navier–Stokes equations with no flow. In this paper, such models with acoustic losses are applied to an acoustic metamaterial. Metamaterials are s...
A newly developed Boundary Element Method formulation includes viscous and thermal losses. The formulation have a requirement for the smoothness of computed geometry, mainly corners and edges is difficult. A requirement of inter element differentiability is given. This project investigates the possibility to enhance computations including edges and...
Projects
Projects (3)
Development of a numerical shape optimization tool for large-scale vibro-acoustic problems
The project is aimed at building a framework to perform shape optimization for acoustic problems and investigate the effect of viscothermal losses in combination with shape optimization.
The goal of the project is to improve already existing Boundary Element models including viscous and thermal dissipation. Current models rely on the so-called Kirchhoff decomposition of the full linearized Navier-Stokes equations coupled through the boundary conditions using finite difference tangential pressure derivatives. By utilizing an extra set of hypersingular tangential derivative boundary integral equations it should be possible to remove the usage of finite difference to couple the equations.
