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Related papers: Glimm's Method for Relativistic Hydrodynamics

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We describe an implicit general relativistic hydrodynamics code. The evolution equations are formulated in comoving coordinates. A conservative finite differencing of the Einstein equations is outlined, and artificial viscosity and…

Astrophysics · Physics 2010-05-12 Matthias Liebendoerfer , Stephan Rosswog , Friedrich-Karl Thielemann

We present a method for parametrizing sub-grid processes in the Shallow Water equations. We define coarse variables and local spatial averages and use a feed-forward neural network to learn sub-grid fluxes. Our method results in a local…

Fluid Dynamics · Physics 2026-05-06 Md Amran Hossan Mojamder , Zhihang Xu , Min Wang , Ilya Timofeyev

The goal of this paper is to discuss some of the results in [31] and [32] and expand upon the work there by proving a global weak existence result as well as a first bubbling analysis in finite time. In addition, an alternative local…

Analysis of PDEs · Mathematics 2021-12-17 Jerome Wettstein

We evaluate an efficient overset grid method for two-dimensional and three-dimensional particulate flows for small numbers of particles at finite Reynolds number. The rigid particles are discretised using moving overset grids overlaid on a…

Computational Physics · Physics 2017-05-24 A. R. Koblitz , S. Lovett , N. Nikiforakis , W. D. Henshaw

LiDAR odometry can achieve accurate vehicle pose estimation for short driving range or in small-scale environments, but for long driving range or in large-scale environments, the accuracy deteriorates as a result of cumulative estimation…

Robotics · Computer Science 2023-03-16 Lizhou Liao , Chunyun Fu , Binbin Feng , Tian Su

Shear-thinning is an important rheological property of many biological fluids, such as mucus, whereby the apparent viscosity of the fluid decreases with shear. Certain microscopic swimmers have been shown to progress more rapidly through…

Fluid Dynamics · Physics 2013-09-06 Thomas D. Montenegro-Johnson , Daniel Loghin , David J. Smith

We analyze the linear stability of monoclinal traveling waves on a constant incline, which connect uniform flowing regions of differing depths. The classical shallow-water equations are employed, subject to a general resistive drag term.…

Fluid Dynamics · Physics 2022-05-18 Jake Langham , Andrew J. Hogg

The Stein Variational Gradient Descent (SVGD) algorithm is a deterministic particle method for sampling. However, a mean-field analysis reveals that the gradient flow corresponding to the SVGD algorithm (i.e., the Stein Variational Gradient…

Machine Learning · Statistics 2024-05-10 Ye He , Krishnakumar Balasubramanian , Bharath K. Sriperumbudur , Jianfeng Lu

We present a powerful new tool for fitting broadband gamma-ray burst afterglow data, which can be used to determine the burst explosion parameters and the synchrotron radiation parameters. By making use of scale invariance between…

High Energy Astrophysical Phenomena · Physics 2015-05-30 H. J. van Eerten , A. J. van der Horst , A. I. MacFadyen

Generalized hydrodynamic theory, which does not rest on the requirement of a local equilibrium, is derived in the long-wave limit of a kinetic equation. The theory bridges the whole frequency range between the quasistatic (Navier-Stokes)…

Soft Condensed Matter · Physics 2009-10-31 I. V. Tokatly , O. Pankratov

Traditional manifold learning algorithms often bear an assumption that the local neighborhood of any point on embedded manifold is roughly equal to the tangent space at that point without considering the curvature. The curvature indifferent…

Machine Learning · Computer Science 2018-03-20 Yangyang Li , Ruqian Lu

Equilibrium solutions are believed to structure the pathways for ergodic trajectories in a dynamical system. However, equilibria are atypical for systems with continuous symmetries, i.e. for systems with homogeneous spatial dimensions,…

Fluid Dynamics · Physics 2017-05-04 Ashley P. Willis , Kimberly Y. Short , Predrag Cvitanović

It is not clear yet why ADAM-alike adaptive gradient algorithms suffer from worse generalization performance than SGD despite their faster training speed. This work aims to provide understandings on this generalization gap by analyzing…

Machine Learning · Computer Science 2021-11-30 Pan Zhou , Jiashi Feng , Chao Ma , Caiming Xiong , Steven Hoi , Weinan E

A theoretical and numerical study of complex sliding flows of yield-stress fluids is presented. Yield-stress fluids are known to slide over solid surfaces if the tangential stress exceeds the {\it sliding yield stress}. The sliding may…

Fluid Dynamics · Physics 2021-02-24 Emad Chaparian , Outi Tammisola

In this paper, we investigate the effects of rapid rotation (Mach number M ~ 1) on plasma fluid stability, focusing specifically on Kelvin-Helmholtz (KH) and interchange instabilities - including both magnetic-curvature-driven (CDI) and…

Plasma Physics · Physics 2026-03-17 Edward A. Tocco , Benjamin D. Dudson , Ian G. Abel , Ben Zhu

Symbolic regression (SR) methods have been extensively investigated to explore explicit algebraic Reynolds stress models (EARSM) for turbulence closure of Reynolds-averaged Navier-Stokes (RANS) equations. The deduced EARSM can be readily…

Fluid Dynamics · Physics 2024-10-15 Yu Zhang , Kefeng Zheng , Fei Liu , Qingfu Zhang , Zhenkun Wang

The squirmer is a simple yet instructive model for microswimmers, which employs an effective slip velocity on the surface of a spherical swimmer to describe its self-propulsion. We solve the hydrodynamic flow problem with the lattice…

Fluid Dynamics · Physics 2019-04-15 Michael Kuron , Philipp Stärk , Christian Burkard , Joost de Graaf , Christian Holm

In this paper, the driven cavity problem was solved using finite difference scheme in stream function-vorticity formulation. A variable grid is adopted to capture more details and information in the area nearby the wall. The Navier-Stokes…

Fluid Dynamics · Physics 2024-07-16 Zirui Mao

Stochastic gradient descent (SGD) is widely used in machine learning. Although being commonly viewed as a fast but not accurate version of gradient descent (GD), it always finds better solutions than GD for modern neural networks. In order…

Machine Learning · Computer Science 2018-08-17 Robert Kleinberg , Yuanzhi Li , Yang Yuan

The treatment of mixing processes is still one of the major uncertainties in 1D stellar evolution models. This is mostly due to the need to parametrize and approximate aspects of hydrodynamics in hydrostatic codes. In particular, the effect…

Solar and Stellar Astrophysics · Physics 2017-08-02 Philipp V. F. Edelmann , Friedrich K. Roepke , Raphael Hirschi , Cyril Georgy , Samuel Jones
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