Hermite regularization of the lattice Boltzmann method for open source computational aeroacoustics

Brogi, Federico; Malaspinas, Orestis; Chopard, Bastien; Bonadonna, Costanza

doi:10.1121/1.5006900

Cited by 30 publications

(29 citation statements)

References 83 publications

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“…isothermal NS, thermal NS or even beyond NS 32 ). In this study, we use an optimized version of the standard LBM for aeroacoustic computations which is valid for isothermal fluid flow in the weakly compressible regimes ( ) 33 . In the case that pressure fluctuations are causing a significant temperature change, and hence affecting the sound speed, the model is expected to generate instabilities inducing divergence in the computational procedure.…”

Section: Methodsmentioning

confidence: 99%

Lattice Boltzmann modeling to explain volcano acoustic source

Brogi

Ripepe

Bonadonna

2018

Sci Rep

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Acoustic pressure is largely used to monitor explosive activity at volcanoes and has become one of the most promising technique to monitor volcanoes also at large scale. However, no clear relation between the fluid dynamics of explosive eruptions and the associated acoustic signals has yet been defined. Linear acoustic has been applied to derive source parameters in the case of strong explosive eruptions which are well-known to be driven by large overpressure of the magmatic fluids. Asymmetric acoustic waveforms are generally considered as the evidence for supersonic explosive dynamics also for small explosive regimes. We have used Lattice-Boltzmann modeling of the eruptive fluid dynamics to analyse the acoustic wavefield produced by different flow regimes. We demonstrate that acoustic waveform well reproduces the flow dynamics of a subsonic fluid injection related to discrete explosive events. Different volumetric flow rate, at low-Mach regimes, can explain both the observed symmetric and asymmetric waveform. Hence, asymmetric waveforms are not necessarily related to the shock/supersonic fluid dynamics of the source. As a result, we highlight an ambiguity in the general interpretation of volcano acoustic signals for the retrieval of key eruption source parameters, necessary for a reliable volcanic hazard assessment.

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Section: Methodsmentioning

confidence: 99%

Lattice Boltzmann modeling to explain volcano acoustic source

Brogi

Ripepe

Bonadonna

2018

Sci Rep

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“…These methods achieve second-order spatial accuracy, yet resulting in a small numerical dissipation similar to a 6 ℎ order optimized Navier-Stokes schemes [29], making LBM highly suitable for aeroacoustic predictions [30]. However classical BGK-LBM collision models can produce high frequency instabilities [31] when viscosity is low. As a consequence, a recursive and regularized BGK model (rrBGK-LBM) [32] is applied to maintain code stability with low numerical dissipation.…”

Section: Dataset Generationmentioning

confidence: 99%

Predicting the propagation of acoustic waves using deep convolutional neural networks

Alguacil

Bauerheim

Jacob

et al. 2021

Journal of Sound and Vibration

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A novel approach for numerically propagating acoustic waves in two-dimensional quiescent media has been developed through a fully convolutional multi-scale neural network. This datadriven method managed to produce accurate results for long simulation times with a database of Lattice Boltzmann temporal simulations of propagating Gaussian Pulses, even in the case of initial conditions unseen during training time, such as the plane wave configuration or the two initial Gaussian pulses of opposed amplitudes. Two different choices of optimization objectives are compared, resulting in an improved prediction accuracy when adding the spatial gradient difference error to the traditional mean squared error loss function. Further accuracy gains are observed when performing an a posteriori correction on the neural network prediction based on the conservation of acoustic energy, indicating the benefit of including physical information in data-driven methods. Nomenclature= Gaussian pulse half-width 0

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“…This recursive approach was proven to increase the numerical stability of LBMs as compared to the original regularized collision model [69]. It was further shown to be competitive against state of the art Navier-Stokes and LBM solvers for the simulation of jet noise [70]. This confirmed its capability for high fidelity simulations, including computational aeroacoustics of moderate to high Reynods number flows.…”

Section: Introductionmentioning

confidence: 96%

Comprehensive comparison of collision models in the lattice Boltzmann framework: Theoretical investigations

2019

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Over the last decades, several types of collision models have been proposed to extend the validity domain of the lattice Boltzmann method (LBM), each of them being introduced in its own formalism. The present article proposes a formalism that describes all these methods within a common mathematical framework, and in this way allows us to draw direct links between them. Here, the focus is put on single and multirelaxation time collision models in either their raw moment, central moment, cumulant or regularized form. In parallel with that, several bases (non orthogonal, orthogonal, Hermite) are considered for the polynomial expansion of populations. General relationships between moments are first derived to understand how moment spaces are related to each other. In addition, a review of collision models further sheds light on collision models that can be rewritten in a linear matrix form. More quantitative mathematical studies are then carried out by comparing explicit expressions for the post collision populations. Thanks to this, it is possible to deduce the impact of both the polynomial basis (raw, Hermite, central, central Hermite, cumulant) and the inclusion of regularization steps on isothermal LBMs. Extensive results are provided for the D1Q3, D2Q9, and D3Q27 lattices, the latter being further extended to the D3Q19 velocity discretization. Links with the most common two and multirelaxation time collision models are also provided for the sake of completeness. The present work ends by emphasizing the importance of an accurate representation of the equilibrium state, independently of the choice of moment space. As an addition to the theoretical purpose of the present article, general instructions are provided to help the reader with the implementation of the most complicated collision models.

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Hermite regularization of the lattice Boltzmann method for open source computational aeroacoustics

Cited by 30 publications

References 83 publications

Lattice Boltzmann modeling to explain volcano acoustic source

Lattice Boltzmann modeling to explain volcano acoustic source

Predicting the propagation of acoustic waves using deep convolutional neural networks

Comprehensive comparison of collision models in the lattice Boltzmann framework: Theoretical investigations

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