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We develop a high order accurate numerical method for solving the elastic wave equation in second-order form. We hybridize the computationally efficient Cartesian grid formulation of finite differences with geometrically flexible…

Numerical Analysis · Mathematics 2025-02-04 Andreas Granath , Siyang Wang

In this work, we analyze an unfitted discontinuous Galerkin discretization for the numerical solution of the Stokes system based on equal higher-order discontinuous velocities and pressures. This approach combines the best from both worlds,…

Numerical Analysis · Mathematics 2022-04-06 Aikaterini Aretaki , Efthymios N. Karatzas , Georgios Katsouleas

Most of numerical methods for deterministic simulations of rarefied gas flows use the discrete velocity (or discrete ordinate) approximation. In this approach, the kinetic equation is approximated with a global velocity grid. The grid must…

Numerical Analysis · Mathematics 2014-03-19 Stéphane Brull , Luc Mieussens

Sparse-grid methods have recently gained interest in reducing the computational cost of solving high-dimensional kinetic equations. In this paper, we construct adaptive and hybrid sparse-grid methods for the Vlasov-Poisson-Lenard-Bernstein…

Unstructured grid ocean models are advantageous for simulating the coastal ocean and river-estuary-plume systems. However, unstructured grid models tend to be diffusive and/or computationally expensive which limits their applicability to…

Atmospheric and Oceanic Physics · Physics 2018-10-31 Tuomas Kärnä , Stephan C. Kramer , Lawrence Mitchell , David A. Ham , Matthew D. Piggott , António M. Baptista

Discontinuous Galerkin (DG) discretizations with exact representation of the geometry and local polynomial degree adaptivity are revisited. Hybridization techniques are employed to reduce the computational cost of DG approximations and…

Numerical Analysis · Mathematics 2019-08-20 Matteo Giacomini , Ruben Sevilla

The Galerkin difference (GD) basis is a set of continuous, piecewise polynomials defined using a finite difference like grid of degrees of freedom. The one dimensional GD basis functions are naturally extended to multiple dimensions using…

Numerical Analysis · Mathematics 2021-06-03 Jeremy E. Kozdon , Lucas C. Wilcox , Thomas Hagstrom , Jeffrey W. Banks

We introduce an immersed high-order discontinuous Galerkin method for solving the compressible Navier-Stokes equations on non-boundary-fitted meshes. The flow equations are discretised with a mixed discontinuous Galerkin formulation and are…

Numerical Analysis · Mathematics 2020-01-08 Hong Xiao , Eky Febrianto , Qiaoling Zhang , Fehmi Cirak

In this paper, we derive a new drift-kinetic method for estimating gradients in the plasma properties through a velocity space distribution at a single point. The gradients are intrinsically related to agyrotropic features of the…

Plasma Physics · Physics 2020-07-13 Blake A. Wetherton , Jan Egedal , Peter K. Montag , Ari Le , William S. Daughton

A high-order quasi-conservative discontinuous Galerkin (DG) method is proposed for the numerical simulation of compressible multi-component flows. A distinct feature of the method is a predictor-corrector strategy to define the grid…

Numerical Analysis · Mathematics 2021-01-18 Dongmi Luo , Shiyi Li , Weizhang Huang , Jianxian Qiu , Yibing Chen

We present a compatible space-time hybridizable/embedded discontinuous Galerkin discretization for nonlinear free-surface waves. We pose this problem in a two-fluid (liquid and gas) domain and use a time-dependent level-set function to…

Numerical Analysis · Mathematics 2023-07-10 Giselle Sosa Jones , Sander Rhebergen

We discuss the mathematical modeling and numerical discretization of transport problems on one-dimensional networks. Suitable coupling conditions are derived that guarantee conservation of mass across network junctions and dissipation of a…

Numerical Analysis · Mathematics 2020-01-23 Herbert Egger , Nora Philippi

We introduce a family of mixed methods and discontinuous Galerkin discretisations designed to numerically solve the Oseen equations written in terms of velocity, vorticity, and Bernoulli pressure. The unique solvability of the continuous…

Numerical Analysis · Mathematics 2020-03-20 Veronica Anaya , Afaf Bouharguane , David Mora , Carlos Reales , Ricardo Ruiz Baier , Nour Seloula , Hector Torres

Numerical simulation of flow problems and wave propagation in heterogeneous media has important applications in many engineering areas. However, numerical solutions on the fine grid are often prohibitively expensive, and multiscale model…

Numerical Analysis · Mathematics 2019-09-30 Siu Wun Cheung , Eric T. Chung , Wing Tat Leung

A conservative discontinuous Galerkin scheme for a nonlinear Dougherty collision operator in full-f long-wavelength gyrokinetics is presented. Analytically this model operator has the advective-diffusive form of Fokker-Planck operators, it…

The quasilinear theory describes the resonant interaction between particles and waves with two coupled equations: one for the evolution of the particle probability density function(\textit{pdf}), the other for the wave spectral energy…

Computational Physics · Physics 2023-10-25 Kun Huang , Michael Abdelmalik , Boris Breizman , Irene M. Gamba

In this paper, some theoretical aspects will be addressed for the asymptotic preserving DG-IMEX schemes recently proposed in [J. Jang, F. Li, J.-M. Qiu and T. Xiong, submitted, arxiv:1306.0227] for kinetic transport equations under a…

Numerical Analysis · Mathematics 2014-06-12 Juhi Jang , Fengyan Li , Jing-Mei Qiu , Tao Xiong

This work proposes a novel variational approximation of partial differential equations on moving geometries determined by explicit boundary representations. The benefits of the proposed formulation are the ability to handle large…

Computational Engineering, Finance, and Science · Computer Science 2024-06-04 Santiago Badia , Pere A. Martorell , Francesc Verdugo

We extend the positivity-preserving method of Zhang & Shu (2010, JCP, 229, 3091-3120) to simulate the advection of neutral particles in phase space using curvilinear coordinates. The ability to utilize these coordinates is important for…

Computational Physics · Physics 2015-06-23 Eirik Endeve , Cory D. Hauck , Yulong Xing , Anthony Mezzacappa

In this paper, we generalize the idea in our previous work for the Vlasov-Amp\`{e}re (VA) system \cite{cheng_va} and develop energy-conserving discontinuous Galerkin (DG) methods for the Vlasov-Maxwell (VM) system. The VM system is a…

Numerical Analysis · Mathematics 2015-06-18 Yingda Cheng , Andrew J. Christlieb , Xinghui Zhong