Unravelling cosmic velocity flows: a Helmholtz–Hodge decomposition algorithm for cosmological simulations

Vallés-Pérez, David; Planelles, S.; Quilis, Vicent

doi:10.1016/j.cpc.2021.107892

Cited by 9 publications

(5 citation statements)

References 42 publications

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“…The Poisson equation for the pressure in incompressible hydrodynamics is another possible application. Similarly, multigrid can be applied to the Hodge-Helmholtz decomposition to extract compressive and solenoidal components from a vector field (e.g., Miniati 2014;Vallés-Pérez et al 2021). We are also planning to implement the particle-mesh gravity solver with AMR combining the multigrid gravity solver and the particle module of Athena++.…”

Section: Summary and Discussionmentioning

confidence: 99%

The Athena++ Adaptive Mesh Refinement Framework: Multigrid Solvers for Self-gravity

Tomida

Stone

2023

ApJS

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We describe the implementation of multigrid solvers in the Athena++ adaptive mesh refinement (AMR) framework and their application to the solution of the Poisson equation for self-gravity. The new solvers are built on top of the AMR hierarchy and TaskList framework of Athena++ for efficient parallelization. We adopt a conservative formulation for the Laplacian operator that avoids artificial accelerations at level boundaries. Periodic, fixed, and zero-gradient boundary conditions are implemented, as well as open boundary conditions based on a multipole expansion. Hybrid parallelization using both Message Passing Interface and OpenMP is adopted, and we present results of tests demonstrating the accuracy and scaling of the methods. On a uniform grid, we show that multigrid significantly outperforms methods based on fast Fourier transforms, and requires only a small fraction of the computing time required by the (highly optimized) magnetohydrodynamic solver in Athena++. As a demonstration of the capabilities of the methods, we present the results of a test calculation of magnetized protostellar collapse on an adaptive mesh.

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Section: Summary and Discussionmentioning

confidence: 99%

The Athena++ Adaptive Mesh Refinement Framework: Multigrid Solvers for Self-gravity

Tomida

Stone

2023

ApJS

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“…At z 0, no important mergers have occurred recently and the ICM has relaxed to a nearly spherical shape, with extended accretion shock radii as well. A series of inner shocks, propagating outwards, are reflexed as density discontinuities (see also the compressive and solenoidal velocity magnitude maps in Vallés-Pérez et al 2021). Solenoidal motions, showing eddies on a wide range of scales, dominate in the volume bounded by the outermost shocks; not only in the central regions of the cluster, but also near the shocks and around filaments.…”

Section: Distribution Of Enstrophy and Helicitymentioning

confidence: 99%

“…In order to split the velocity field in its compressive and solenoidal components, we perform a Helmholtz-Hodge decomposition (HHD). Our implementation, presented in Vallés-Pérez et al (2021), does so by solving an elliptic equation for the scalar potential, φ, which generates the compressive velocity, vcomp = −∇φ; and one elliptic equation for each cartesian component of the vector potential, A, which is responsible for the solenoidal (or rotational) velocity component, vrot = ∇ × A.…”

Section: Helmholtz-hodge Decomposition In An Amr Multigridmentioning

confidence: 99%

“…All the derivatives are computed using high-order stencils to damp their contamination due to high-frequency noise. A more complete description and a set of tests can be found in Vallés-Pérez et al (2021).…”

Section: Helmholtz-hodge Decomposition In An Amr Multigridmentioning

confidence: 99%

“…2.1, yielding the solenoidal and compressive turbulent velocity fields, respectively. The routines for applying this filtering scheme have been included in the publicly available code vortex 7 (Vallés-Pérez et al 2021).…”

Section: Multi-scale Filteringmentioning

confidence: 99%

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Troubled cosmic flows: turbulence, enstrophy and helicity from the assembly history of the intracluster medium

Vallés-Pérez,

Planelles,

Quilis

2021

Preprint

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Both simulations and observations have shown that turbulence is a pervasive phenomenon in cosmic scenarios, yet it is particularly difficult to model numerically due to its intrinsically multiscale character which demands high resolutions. Additionally, turbulence is tightly connected to the dynamical state and the formation history of galaxies and galaxy clusters, producing a diverse phenomenlogy which requires large samples of such structures to attain robust conclusions. In this work, we use an adaptive mesh refinement (AMR) cosmological simulation to explore the generation and dissipation of turbulence in galaxy clusters, in connection to its assembly history. We find that major mergers, and more generally accretion of gas, is the main process driving turbulence in the ICM. We have especially focused on solenoidal turbulence, which can be quantified through enstrophy. Our results seem to confirm a scenario for its generation which involves baroclinicity and compression at the external (accretion) and internal (merger) shocks, followed by vortex stretching downstream of them. We have also looked at the infall of mass to the cluster beyond its virial boundary, finding that gas follows trajectories with some degree of helicity, as it has already developed some vorticity in the external shocks.

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Passive decomposition and gradient control of fractional-order nonlinear systems

et al. 2022

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Unravelling cosmic velocity flows: a Helmholtz–Hodge decomposition algorithm for cosmological simulations

Cited by 9 publications

References 42 publications

The Athena++ Adaptive Mesh Refinement Framework: Multigrid Solvers for Self-gravity

The Athena++ Adaptive Mesh Refinement Framework: Multigrid Solvers for Self-gravity

Troubled cosmic flows: turbulence, enstrophy and helicity from the assembly history of the intracluster medium

Passive decomposition and gradient control of fractional-order nonlinear systems

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