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A new approach of implementing initial and boundary conditions for the lattice Boltzmann method is presented. The new approach is based on an extended collision operator that uses the gradients of the fluid velocity. The numerical…

comp-gas · Physics 2009-10-22 P. A. Skordos

We propose a Hermite spectral method for the inelastic Boltzmann equation, which makes two-dimensional periodic problem computation affordable by the hardware nowadays. The new algorithm is based on a Hermite expansion, where the expansion…

Numerical Analysis · Mathematics 2023-08-15 Ruo Li , Yixiao Lu , Yanli Wang

A type of discrete Boltzmann model for simulating shallow water flows is derived by using the Hermite expansion approach. Through analytical analysis, we study the impact of truncating distribution function and discretizing particle…

Fluid Dynamics · Physics 2018-07-16 Jianping Meng , Xiao-Jun Gu , David R Emerson , Yong Peng , Jianmin Zhang

We introduce a novel strategy for cosmological Boltzmann codes leading to an increase in speed by a factor of \sim 30 for small scale Fourier modes. We (re-)investigate the tight coupling approximation and obtain analytic formulae reaching…

Astrophysics · Physics 2009-11-10 Michael Doran

In this paper, we improve upon the discontinuous Galerkin (DG) method for Hamilton-Jacobi (HJ) equation with convex Hamiltonians in (Y. Cheng and C.-W. Shu, J. Comput. Phys. 223:398-415,2007) and develop a new DG method for directly solving…

Numerical Analysis · Mathematics 2015-06-17 Yingda Cheng , Zixuan Wang

This paper proposes semi-discrete and fully discrete hybridizable discontinuous Galerkin (HDG) methods for the Burgers' equation in two and three dimensions. In the spatial discretization, we use piecewise polynomials of degrees $ k \ (k…

Numerical Analysis · Mathematics 2021-02-02 Zimo Zhu , Gang Chen , Xiaoping Xie

We present an immersed interface method for the vorticity-velocity form of the 2D Navier Stokes equations that directly addresses challenges posed by multiply connected domains, nonconvex obstacles, and the calculation of force…

Fluid Dynamics · Physics 2022-07-13 James Gabbard , Thomas Gillis , Philippe Chatelain , Wim M. van Rees

In this paper, we propose a unified framework, the Hessian discretisation method (HDM), which is based on four discrete elements (called altogether a Hessian discretisation) and a few intrinsic indicators of accuracy, independent of the…

Numerical Analysis · Mathematics 2018-08-28 Jérôme Droniou , Bishnu P. Lamichhane , Devika Shylaja

This paper constitutes a step in the direction of developing integer lattice gas methods as an attractive alternative to lattice Boltzmann methods. Here we show that to Boltzmann limit the one dimensional Blommel integer lattice gas is very…

Fluid Dynamics · Physics 2025-10-28 Noah Seekins , Alexander J. Wagner

The fast multipole method (FMM) has had great success in reducing the computational complexity of solving the boundary integral form of the Helmholtz equation. We present a formulation of the Helmholtz FMM that uses Fourier basis functions…

Numerical Analysis · Mathematics 2014-03-20 Cris Cecka , Eric Darve

A global solution of the Schr\"odinger equation for explicitly time-dependent Hamiltonians is derived by integrating the non-linear differential equation associated with the time-dependent wave operator. A fast iterative solution method is…

Quantum Physics · Physics 2015-05-18 Arnaud Leclerc , Georges Jolicard

A numerically stable method to solve the discretized Boltzmann-Enskog equation describing the behavior of non ideal fluids under inhomogeneous conditions is presented. The algorithm employed uses a Lagrangian finite-difference scheme for…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Simone Melchionna , Umberto Marini Bettolo Marconi

High order methods based on diagonal-norm summation by parts operators can be shown to satisfy a discrete conservation or dissipation of entropy for nonlinear systems of hyperbolic PDEs. These methods can also be interpreted as nodal…

Numerical Analysis · Mathematics 2020-06-24 Jesse Chan

The central framework of a filtered lattice Boltzmann collision operator formulation is to remove hydrodynamic moments that are not supported by the order of isotropy of a given lattice velocity set. Due to the natural moment orthogonality…

Fluid Dynamics · Physics 2020-02-10 Hudong Chen , Raoyang Zhang , Pradeep Gopalakrishnan

High-dimensional partial-differential equations (PDEs) arise in a number of fields of science and engineering, where they are used to describe the evolution of joint probability functions. Their examples include the Boltzmann and…

Numerical Analysis · Mathematics 2018-10-17 A. M. P. Boelens , D. Venturi , D. M. Tartakovsky

We construct quasi-Monte Carlo methods to approximate the expected values of linear functionals of Galerkin discretizations of parametric operator equations which depend on a possibly infinite sequence of parameters. Such problems arise in…

Numerical Analysis · Mathematics 2015-03-10 Josef Dick , Frances Y. Kuo , Quoc T. Le Gia , Dirk Nuyens , Christoph Schwab

We propose a novel discretization procedure for the classical Euler equation based on the theory of Galois differential algebras and the finite operator calculus developed by G.C. Rota and collaborators. This procedure allows us to define…

Mathematical Physics · Physics 2025-07-09 Miguel A. Rodríguez , Piergiulio Tempesta

This paper presents a novel Fourier spectral method that utilizes optimization techniques to ensure the positivity and conservation of moments in the space of trigonometric polynomials. We rigorously analyze the accuracy of the new method…

Numerical Analysis · Mathematics 2023-04-25 Zhenning Cai , Bo Lin , Meixia Lin

In this paper we show that standard implementations of fluctuating Lattice Boltzmann methods do not obey Galilean invariance at a fundamental level. In trying to remedy this we are led to a novel kind of multi-relaxation time lattice…

Computational Physics · Physics 2013-08-09 G. Kaehler , A. J. Wagner

In a recent paper we presented a new ultra efficient numerical method for solving kinetic equations of the Boltzmann type (G. Dimarco, R. Loubere, Towards an ultra efficient kinetic scheme. Part I: basics on the 689 BGK equation, J. Comp.…

Numerical Analysis · Mathematics 2015-06-12 Giacomo Dimarco , Raphaël Loubere