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In ordinary turbulence research it has been a long standing tradition to solve the equations in spectral space giving the best possible accuracy. This is indeed a natural choice for incompressible problems with periodic boundaries, but it…

Astrophysics · Physics 2009-11-07 A. Brandenburg , W. Dobler

We present a graph-based numerical method for solving hyperbolic systems of conservation laws using discontinuous finite elements. This work fills important gaps in the theory as well as practice of graph-based schemes. In particular, four…

Numerical Analysis · Mathematics 2025-05-21 Martin Kronbichler , Matthias Maier , Ignacio Tomas

Theory predicts rapid genetic drift during invasions, yet many expanding populations maintain high genetic diversity. We find that genetic drift is dramatically suppressed when dispersal rates increase with the population density because…

Populations and Evolution · Quantitative Biology 2019-03-29 Gabriel Birzu , Sakib Matin , Oskar Hallatschek , Kirill S. Korolev

The Langevin dynamics is a diffusion process extensively used, in particular in molecular dynamics simulations, to sample Gibbs measures. Some alternatives based on (piecewise deterministic) kinetic velocity jump processes have gained…

Numerical Analysis · Mathematics 2025-05-27 Nicolaï Gouraud , Lucas Journel , Pierre Monmarché

The energy method can be used to identify well-posed initial boundary value problems for quasi-linear, symmetric hyperbolic partial differential equations with maximally dissipative boundary conditions. A similar analysis of the discrete…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Luis Lehner , David Neilsen , Oscar Reula , Manuel Tiglio

When fully conservative methods are used to simulate transcritical flow, spurious pressure oscillations and numerical instability are generated. The strength and speed of propagation of shock waves cannot be represented correctly using a…

Fluid Dynamics · Physics 2022-06-24 Bonan Xu , Hanhui Jin , Yu Guo , Jianren Fan

In this paper we study the problem of computing the effective diffusivity for a particle moving in chaotic and stochastic flows. In addition we numerically investigate the residual diffusion phenomenon in chaotic advection. The residual…

Numerical Analysis · Mathematics 2017-11-28 Zhongjian Wang , Jack Xin , Zhiwen Zhang

Singularly perturbed problems are known to have solutions with steep boundary layers that are hard to resolve numerically. Traditional numerical methods, such as Finite Difference Methods (FDMs), require a refined mesh to obtain stable and…

Numerical Analysis · Mathematics 2024-09-13 Jiajing Guan , Howard Elman

Numerical simulation of viscoelastic flows is challenging because of the hyperbolic nature of viscoelastic constitutive equations. Despite their superior accuracy and efficiency, pseudo-spectral methods require the introduction of…

Fluid Dynamics · Physics 2020-10-20 Lu Zhu , Li Xi

Deep generative models, such as diffusion models, GANs, and IMLE, have shown impressive capability in tackling inverse problems. However, the validity of model-generated solutions w.r.t. the forward problem and the reliability of associated…

Machine Learning · Computer Science 2023-12-21 Shichong Peng , Alireza Moazeni , Ke Li

We address in this paper a model for the simulation of turbulent deflagrations in industrial applications. The flow is governed by the Euler equations for a variable composition mixture and the combustion modelling is based on a…

Numerical Analysis · Mathematics 2020-10-16 D Grapsas , Raphaèle Herbin , J. -C Latché , Y Nasseri

In numerical magnetohydrodynamics (MHD), a major challenge is maintaining zero magnetic field-divergence (div-B). Constrained transport (CT) schemes can achieve this at high accuracy, but have generally been restricted to very specific…

Instrumentation and Methods for Astrophysics · Physics 2017-07-11 Philip F. Hopkins

We devise and analyze a class of the primal discontinuous Galerkin methods for the magnetic advection-diffusion problems based on the weighted-residual approach. In addition to the upwind stabilization, we find a new mechanism under the…

Numerical Analysis · Mathematics 2022-08-03 Jindong Wang , Shuonan Wu

We consider numerical methods for linear parabolic equations in one spatial dimension having piecewise constant diffusion coefficients defined by a one parameter family of interface conditions at the discontinuity. We construct immersed…

Numerical Analysis · Mathematics 2013-10-31 V. A. Bokil , N. L. Gibson , S. L. Nguyen , E. A. Thomann , E. Waymire

This paper shows how to evolve numerically the maximum entropy probability distributions for a given set of constraints, which is a variational calculus problem. An evolutionary algorithm can obtain approximations to some well-known…

Methodology · Statistics 2020-02-07 Raul Rojas

Our study is dedicated to the probabilistic representation and numerical approximation of solutions to coupled systems of variational inequalities. The dynamics of each component of the solution is driven by a different linear parabolic…

Probability · Mathematics 2014-01-10 Romuald Elie , Idris Kharroubi

The inverse problem of backward diffusion is known to be ill-posed and highly unstable. Backward diffusion processes appear naturally in image enhancement and deblurring applications. It is therefore greatly desirable to establish a…

Numerical Analysis · Mathematics 2020-06-18 Leif Bergerhoff , Marcelo Cárdenas , Joachim Weickert , Martin Welk

Stochastic diffusion equations are crucial for modeling a range of physical phenomena influenced by uncertainties. We introduce the generalized finite difference method for solving these equations. Then, we examine its consistency,…

Numerical Analysis · Mathematics 2024-11-22 Faezeh Nassajian Mojarrad

A finite difference scheme for the numerical treatment of the (3+1)D Dirac equation is presented. Its staggered-grid intertwined discretization treats space and time coordinates on equal footing, thereby avoiding the notorious fermion…

Computational Physics · Physics 2015-06-09 René Hammer , Walter Pötz , Anton Arnold

The construction of numerical schemes for the Kuramoto model is challenging due to the structural properties of the system which are essential in order to capture the correct physical behavior, like the description of stationary states and…

Numerical Analysis · Mathematics 2018-11-14 José A. Carrillo , Young-Pil Choi , Lorenzo Pareschi