English
Related papers

Related papers: Unravelling cosmic velocity flows: a Helmholtz-Hod…

200 papers

We present the first results of one extremely high resolution, non-radiative magnetohydrodynamical cosmological zoom-in simulation of a massive cluster with a virial mass M$_\mathrm{vir} = 2.0 \times 10^{15}$ solar masses. We adopt a mass…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Ulrich P. Steinwandel , Klaus Dolag , Ludwig Böss , Tirso Marin-Gilabert

We introduce the cosmological HYPER code based on an innovative hydro-particle-mesh (HPM) algorithm for efficient and rapid simulations of gas and dark matter. For the HPM algorithm, we update the approach of Gnedin & Hui (1998) to expand…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 Yizhou He , Hy Trac , Nickolay Y. Gnedin

We present a general method for accelerating by more than an order of magnitude the convolution of pixelated functions on the sphere with a radially-symmetric kernel. Our method splits the kernel into a compact real-space component and a…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-31 P. M. Sutter , Benjamin D. Wandelt , Franz Elsner

Getting standard multigrid to work efficiently for the high-frequency Helmholtz equation has been an open problem in applied mathematics for years. Much effort has been dedicated to finding solution methods which can use multigrid…

Numerical Analysis · Mathematics 2023-08-28 Vandana Dwarka , Cornelis Vuik

Potential-based formulation with generalized Lorenz gauge can be used in the quantization of electromagnetic fields in inhomogeneous media. However, one often faces the redundancy of modes when finding eigenmodes from potential-based…

Optics · Physics 2023-01-10 Jie Zhu , Thomas E. Roth , Dong-Yeop Na , Weng Cho Chew

Boundary element methods for the Helmholtz equation lead to large dense matrices that can only be handled if efficient compression techniques are used. Directional compression techniques can reach good compression rates even for…

Numerical Analysis · Mathematics 2020-11-03 Steffen Börm , Christina Börst

In magnetohydrodynamics (MHD), the magnetic field is evolved by the induction equation and coupled to the gas dynamics by the Lorentz force. We perform numerical smoothed particle magnetohydrodynamics (Spmhd) simulations and study the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 F. A. Stasyszyn , K. Dolag , A. M. Beck

We present a new MHD wave decomposition method that overcomes the limitations of existing wave identification methods. Our method allows to investigate the energy fluxes in different MHD modes at different locations of the solar atmosphere…

Solar and Stellar Astrophysics · Physics 2022-04-20 N. Yadav , Rony Keppens , B. Popescu Braileanu

In this work we present a novel methodology that combines Higher Order Singular Value Decomposition (HOSVD) with Deep Learning (DL) techniques for super-resolution in computational fluid dynamics (CFD) and sparse experimental datasets. This…

While geostrophy remains the simplest and most practical balance to extract velocity information from sea-surface height anomaly (SSHa), confusions remain within the oceanographic community to what extent this balance can be applied to…

Atmospheric and Oceanic Physics · Physics 2026-01-27 Takaya Uchida , Badarvada Yadidya , Vadim Bertrand , Jia-Xian Chang , Brian Arbic , Jay Shriver , Julien Le Sommer

A fast method is proposed for solving the high frequency Helmholtz equation. The building block of the new fast method is an overlapping source transfer domain decomposition method for layered medium, which is an extension of the source…

Numerical Analysis · Mathematics 2015-07-10 Wei Leng

This letter presents a new approach using the cosmic peculiar velocity field to characterize the morphology and size of large scale structures in the local Universe. The algorithm developed uses the three-dimensional peculiar velocity field…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-31 A. Dupuy , H. M. Courtois , F. Dupont , F. Denis , R. Graziani , Y. Copin , D. Pomarede , N. Libeskind , E. Carlesi , B. Tully , D. Guinet

We study a solenoidal-potential type decomposition of a symmetric $m$-tensor field in $\Rb^2$, and its implications to injectivity questions for the momentum and elastic ray transforms. For symmetric tensor fields, a general decomposition…

Analysis of PDEs · Mathematics 2026-02-24 Antti Kykkänen , Rohit Kumar Mishra , Suman Kumar Sahoo

We report on results of recent, high resolution hydrodynamic simulations of the formation and evolution of X-ray clusters of galaxies carried out within a cosmological framework. We employ the highly accurate piecewise parabolic method…

Astrophysics · Physics 2009-10-30 Michael L. Norman , Greg L. Bryan

Numerical geodynamo simulations with parameters close to an Earth-like regime would be of great interest for understanding the dynamics of the Earth's liquid outer core and the associated geomagnetic field. Such simulations are far too…

Computational Physics · Physics 2022-06-02 Krasymyr Tretiak , Meredith Plumley , Michael Calkins , Steven Tobias

We propose a defiltering method of turbulent flow fields for Lagrangian particle tracking using machine learning techniques. Numerical simulation of Lagrangian particle tracking is commonly used in various fields. In general, practical…

Fluid Dynamics · Physics 2024-11-21 Tomoya Oura , Koji Fukagata

We introduce the concept of compressed convolution, a technique to convolve a given data set with a large number of non-orthogonal kernels. In typical applications our technique drastically reduces the effective number of computations. The…

Instrumentation and Methods for Astrophysics · Physics 2014-01-08 F. Elsner , B. D. Wandelt

We present a new approach for quantifying the abundance of galaxy clusters and constraining cosmological parameters using dynamical measurements. In the standard method, galaxy line-of-sight (LOS) velocities, $v$, or velocity dispersions…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 M. Ntampaka , H. Trac , J. Cisewski , L. C. Price

Numerical simulation of atmospheric turbulence is one of the biggest bottlenecks in developing computational techniques for solving the inverse problem in long-range imaging. The classical split-step method is based upon numerical wave…

Image and Video Processing · Electrical Eng. & Systems 2022-10-14 Nicholas Chimitt , Xingguang Zhang , Zhiyuan Mao , Stanley H. Chan

We explore the decay of turbulence and magnetic fields generated by fluctuation dynamo action in the context of galaxy clusters where such a decaying phase can occur in the aftermath of a major merger event. Using idealized numerical…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-28 Sharanya Sur