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This paper introduces an Algebraic MultiScale method for simulation of flow in heterogeneous porous media with embedded discrete Fractures (F-AMS). First, multiscale coarse grids are independently constructed for both porous matrix and…

Numerical Analysis · Mathematics 2017-05-17 Matei Tene , Mohammed Saad Al Kobaisi , Hadi Hajibeygi

We investigate the diffusive shock acceleration in the presence of the non-resonant streaming instability introduced by Bell (2004). The numerical MHD simulations of the magnetic field amplification combined with the analytical treatment of…

Astrophysics · Physics 2009-11-13 V. N. Zirakashvili , V. S. Ptuskin

We introduce a Monte Carlo model of nonlinear diffusive shock acceleration allowing for the generation of large-amplitude magnetic turbulence. The model is the first to include strong wave generation, efficient particle acceleration to…

Astrophysics · Physics 2008-11-26 Andrey Vladimirov , Donald C. Ellison , Andrei Bykov

Computational modeling of charged species transport has enabled the analysis, design, and optimization of a diverse array of electrochemical and electrokinetic devices. These systems are represented by the Poisson-Nernst-Planck (PNP)…

Numerical Analysis · Mathematics 2024-01-02 Sungu Kim , Kumar Saurabh , Makrand A. Khanwale , Ali Mani , Robbyn K. Anand , Baskar Ganapathysubramanian

We independently develop a simulation code following the previous dynamical Monte Carlo simulation of the diffusive shock acceleration under the isotropic scattering law during the scattering process, and the same results are obtained.…

Earth and Planetary Astrophysics · Physics 2015-05-20 Xin Wang , Yihua Yan

Diffusion MRI (dMRI) provides the ability to reconstruct neuronal fibers in the brain, $\textit{in vivo}$, by measuring water diffusion along angular gradient directions in q-space. High angular resolution diffusion imaging (HARDI) can…

Machine Learning · Statistics 2018-05-30 Evan Schwab , René Vidal , Nicolas Charon

Computational studies that use block-structured adaptive mesh refinement (AMR) approaches suffer from unnecessarily high mesh resolution in regions adjacent to important solution features. This deficiency limits the performance of AMR…

Computational Physics · Physics 2022-03-02 Brandon Gusto , Tomasz Plewa

Cosmological shock waves play an important role in hierarchical structure formation by dissipating and thermalizing kinetic energy of gas flows, thereby heating the universe. Furthermore, identifying shocks in hydrodynamical simulations and…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-05 Kevin Schaal , Volker Springel

Particle acceleration in relativistic shocks is studied analytically in the test-particle, small-angle scattering limit, for an arbitrary velocity-angle diffusion function D. Accurate analytic expressions for the spectral index s are…

Astrophysics · Physics 2008-11-26 Uri Keshet

Diffusion models (DMs) have shown promising results on single-image super-resolution and other image-to-image translation tasks. Benefiting from more computational resources and longer inference times, they are able to yield more realistic…

Computer Vision and Pattern Recognition · Computer Science 2024-10-24 Yuanting Fan , Chengxu Liu , Nengzhong Yin , Changlong Gao , Xueming Qian

Latent Space (LS) network models project the nodes of a network on a $d$-dimensional latent space to achieve dimensionality reduction of the network while preserving its relevant features. Inference is often carried out within a Markov…

Computation · Statistics 2024-08-23 Roberto Casarin , Antonio Peruzzi

Diffusion models have gained attention for their success in modeling complex distributions, achieving impressive perceptual quality in SR tasks. However, existing diffusion-based SR methods often suffer from high computational costs,…

Computer Vision and Pattern Recognition · Computer Science 2025-05-22 Rui Qin , Qijie Wang , Ming Sun , Haowei Zhu , Chao Zhou , Bin Wang

We have developed a new computer code, RAM, to solve the conservative equations of special relativistic hydrodynamics (SRHD) using adaptive mesh refinement (AMR) on parallel computers. We have implemented a characteristic-wise, finite…

Astrophysics · Physics 2009-11-11 Weiqun Zhang , Andrew I. MacFadyen

Strong non-relativistic shocks are known to accelerate particles up to relativistic energies. However, for Diffusive Shock Acceleration electrons must have a highly suprathermal energy, implying a need for very efficient pre-acceleration.…

Plasma Physics · Physics 2023-10-24 Karol Fulat , Artem Bohdan , Gabriel Torralba Paz , Martin Pohl

Multiphase flows are an important class of fluid flow and their study facilitates the development of diverse applications in industrial, natural, and biomedical systems. We consider a model that uses a continuum description of both phases…

Fluid Dynamics · Physics 2025-08-04 Bindi M. Nagda , Aaron Barrett , Boyce E. Griffith , Aaron L. Fogelson , Jian Du

This paper enhances the Diffuse Interface Method (DIM) for simulating compressible multiphase flows across all Mach numbers by addressing the accuracy challenges posed at low Mach regimes. A correction to the Riemann solver is introduced,…

Numerical Analysis · Mathematics 2025-03-17 Ghanshyam Bharate , J. C. Mandal

The shock waves produce relativistic particles via the diffusive shock acceleration (DSA) mechanism. Among various circumstances, fast acceleration has been expected for perpendicular shocks. We investigate the acceleration time and the…

High Energy Astrophysical Phenomena · Physics 2020-07-15 Shoma F. Kamijima , Yutaka Ohira , Ryo Yamazaki

We have developed a Monte Carlo technique for self-consistently calculating the hydrodynamic structure of oblique, steady-state shocks, together with the first-order Fermi acceleration process and associated non-thermal particle…

Astrophysics · Physics 2009-10-28 Donald C. Ellison , Matthew G. Baring , Frank C. Jones

We have carried out numerical simulations of strongly gravitating systems based on the Einstein equations coupled to the relativistic hydrodynamic equations using adaptive mesh refinement (AMR) techniques. We show AMR simulations of NS…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Edwin Evans , Sai Iyer , Erik Schnetter , Wai-Mo Suen , Jian Tao , Randy Wolfmeyer , Hui-Min Zhang

We present a new code, SCALAR, based on the high-resolution hydrodynamics and N-body code RAMSES, to solve the Schr\"odinger equation on adaptive refined meshes. The code is intended to be used to simulate axion or fuzzy dark matter models…

Computational Physics · Physics 2020-09-23 Mattia Mina , David F. Mota , Hans A. Winther