Improving Absorption of Sound Using Active Control

Friot, Emmanuel; Gintz, Alexandre; Herzog, Philippe; Schneider, Stefan

doi:10.1007/978-1-4020-9438-5_9

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…Hence, the amplitudes of forward scattered waves will be affected, and the resulting (modal) wave propagation cannot be detached from specifics such as the geometry of the laboratory [14]. As these limitations are not inherent to (active) radiation boundary conditions, an active control of the wave field on the edge of the domain e.g., [15][16][17][18][19][20][21] appears more appropriate to mitigate the influence of the boundary. Here, we present a fundamentally new laboratory for physical, real-time, acoustic immersive wave propagation experiments using active boundary control.…”

Section: Introductionmentioning

confidence: 99%

Immersive Wave Propagation Experimentation: Physical Implementation and One-Dimensional Acoustic Results

et al. 2018

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We present a fundamentally new approach to laboratory acoustic and seismic wave experimentation that enables full immersion of a physical wave propagation experiment within a virtual numerical environment. Using a recent theory of immersive boundary conditions that relies on measurements made on an inner closed surface of sensors, the output of numerous closely spaced sources around the physical domain is continuously varied in time and space. This allows waves to seamlessly propagate back and forth between both domains, without being affected by reflections at the boundaries between both domains, which enables us to virtually expand the size of the physical laboratory and operate at much lower frequencies than previously possible (sonic frequencies as low as 1 kHz). While immersive boundary conditions have been rigorously tested numerically, here we present the first proof of concept for their physical implementation with experimental results from a one-dimensional sound wave tube. These experiments demonstrate the performance and capabilities of immersive boundary conditions in canceling boundary reflections and accounting for long-range interactions with a virtual domain outside the physical experiment. Moreover, we introduce a unique high-performance acquisition, computation, and control system that will enable the real-time implementation of immersive boundary conditions in three dimensions. The system is capable of extrapolating wave fields recorded on 800 simultaneous inputs to 800 simultaneous outputs, through arbitrarily complex virtual background media with an extremely low total system latency of 200 μs. The laboratory allows studying a variety of long-standing problems and poorly understood aspects of wave physics and imaging. Moreover, such real-time immersive experimentation opens up exciting possibilities for the future of laboratory acoustic and seismic experiments and for fields such as active acoustic cloaking and holography.

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Section: Introductionmentioning

confidence: 99%

Immersive Wave Propagation Experimentation: Physical Implementation and One-Dimensional Acoustic Results

et al. 2018

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“…1.1 shows that these boundary sources can generate wave energy that exactly annihilates the outgoing waves and their reflections when they arrive at the boundary. This boundary wave absorption is the main goal of developing active anechoic chambers in which waves do not reflect at the boundary of the experimental domain (Guicking & Karcher, 1984;Orduña Bustamante & Nelson, 1992;Bobrovnitskii, 2006;Friot et al, 2009;Habault et al, 2017).…”

Section: Wavefield Control Experimentsmentioning

confidence: 99%

Elastic immersive wave experimentation

Robertsson

Manen

2022

Geophysical Journal International

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We describe an elastic wave propagation laboratory that enables a solid object to be artificially immersed within an extended (numerical) environment such that a physical wave propagation experiment carried out in the solid drives the propagation in the extended (numerical) environment and vice-versa. The underlying method of elastic immersive wave experimentation for such a laboratory involves deploying arrays of active multi-component sources at the traction-free surface of the solid (e.g., a cube of granitic rock). These sources are used to accomplish two tasks: (1) cancel outgoing waves, and (2) emit ingoing waves representing the first-order interactions between the physical and extended domains, computed using, e.g., a finite-difference (FD) method. Higher-order interactions can be built by alternately carrying out the processes for canceling the outgoing waves and the FD simulations for generating the ingoing waves. We validate the proposed iterative scheme for realizing elastic immersive wave experimentation using two-dimensional (2D) synthetic wave experiments.

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Improving Absorption of Sound Using Active Control

Cited by 2 publications

References 4 publications

Immersive Wave Propagation Experimentation: Physical Implementation and One-Dimensional Acoustic Results

Immersive Wave Propagation Experimentation: Physical Implementation and One-Dimensional Acoustic Results

Elastic immersive wave experimentation

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