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We present a new splitting method for time-dependent convection-dominated diffusion problems. The original convection diffusion system is split into two sub-systems: a pure convection system and a diffusion system. At each time step, a…

Mathematical Physics · Physics 2013-02-19 Feng Shi , Guoping Liang , Yubo Zhao , Jun Zou

We consider a general optimal control problem in the setting of gradient flows. Two approximations of the problem are presented, both relying on the variational reformulation of gradient-flow dynamics via the Weighted-Energy-Dissipation…

Optimization and Control · Mathematics 2024-03-25 Takeshi Fukao , Ulisse Stefanelli , Riccardo Voso

In this paper, we analyze two classes of spectral volume (SV) methods for one-dimensional hyperbolic equations with degenerate variable coefficients. The two classes of SV methods are constructed by letting a piecewise $k$-th order ($k\ge…

Numerical Analysis · Mathematics 2022-11-10 Minqiang Xu , Yanting yuan , Waixiang Cao , Qingsong Zou

A general high-order fully explicit scheme based on projective integration methods is here presented to solve systems of degenerate parabolic equations in general dimensions. The method is based on a BGK approximation of the…

Numerical Analysis · Mathematics 2025-03-10 Tommaso Tenna

We consider a variational approach to solve parabolic problems by minimising a functional over time and space. To achieve existence results we investigate the notion of $\mathscr{A}$-quasiconvexity for non-homogeneous operators in…

Analysis of PDEs · Mathematics 2026-02-03 Stefan Schiffer , Espen Xylander

We investigate a variational approach to nonpotential perturbations of gradient flows of nonconvex energies in Hilbert spaces. We prove existence of solutions to elliptic-in-time regularizations of gradient flows by combining the…

Analysis of PDEs · Mathematics 2016-05-04 Stefano Melchionna

This paper is concerned with a strongly degenerate convection-diffusion equation in one space dimension whose convective flux involves a non-linear function of the total mass to one side of the given position. This equation can be…

Numerical Analysis · Mathematics 2010-07-12 Fernando Betancourt , Raimund Bürger , Kenneth H. Karlsen

We will show that the same type of estimates known for the fundamental solutions for scalar parabolic equations with smooth enough coefficients hold for the first order derivatives of fundamental solution with respect to space variables of…

Analysis of PDEs · Mathematics 2009-06-25 Michele Di Cristo , Kyoungsun Kim , Gen Nakamura

We consider a 1D-2V Vlasov-Fokker-Planck multi-species ionic description coupled to fluid electrons. We address temporal stiffness with implicit time stepping, suitably preconditioned. To address temperature disparity in time and space, we…

Plasma Physics · Physics 2018-05-09 William T. Taitano , Luis Chacon , Andrei N. Simakov

This paper presents a semi-implicit spectral deferred correction (SDC) method for incompressible Navier-Stokes problems with variable viscosity and time-dependent boundary conditions. The proposed method integrates elements of velocity- and…

Numerical Analysis · Mathematics 2020-10-28 Jörg Stiller

A singularly perturbed parabolic problem of convection-diffusion type with incompatible inflow boundary and initial conditions is examined. In the case of constant coefficients, a set of singular functions are identified which match certain…

Numerical Analysis · Mathematics 2022-12-20 Jose Luis Gracia , Eugene O'Riordan

This article performs a unified convergence analysis of a variety of numerical methods for a model of the miscible displacement of one incompressible fluid by another through a porous medium. The unified analysis is enabled through the…

Numerical Analysis · Mathematics 2018-03-07 Jérôme Droniou , Robert Eymard , Alain Prignet , Kyle S. Talbot

We present the Method Of Lines (MOL), which is based on the spectral collocation method, to solve space-fractional advection-diffusion equations (SFADEs) on a finite domain with variable coefficients. We focus on the cases in which the…

Numerical Analysis · Mathematics 2019-06-05 Mohammed K. Almoaeet , Mostafa Shamsi , Hassan Khosravian-Arab , Delfim F. M. Torres

The following work compares two popular mixed finite elements used to model subsurface flow and transport in heterogeneous porous media; the lowest order Raviart-Thomas element and the variational multiscale stabilized element. Comparison…

Numerical Analysis · Computer Science 2015-03-17 D. Z. Turner , K. B. Nakshatrala , P. K. Notz

The existence and uniqueness of weak solutions to dynamical low-rank evolution problems for parabolic partial differential equations in two spatial dimensions is shown, covering also non-diagonal diffusion in the elliptic part. The proof is…

Numerical Analysis · Mathematics 2020-12-08 Markus Bachmayr , Henrik Eisenmann , Emil Kieri , André Uschmajew

We study system design problems stated as parameterized stochastic programs with a chance-constraint set. We adopt a Bayesian approach that requires the computation of a posterior predictive integral which is usually intractable. In…

Machine Learning · Statistics 2020-01-07 Prateek Jaiswal , Harsha Honnappa , Vinayak A. Rao

We develop a complete stability theory for two-dimensional periodic traveling waves of reaction-diffusion systems. More precisely, we identify a diffusive spectral stability assumption, prove that it implies nonlinear stability and provide…

Analysis of PDEs · Mathematics 2024-08-28 Benjamin Melinand , L. Miguel Rodrigues

The aim of this paper is to study and classify the multiplicity of distinguished limits and asymptotic solutions for the advection equation with a general oscillating velocity field with the systematic use of the two-timing method. Our…

Fluid Dynamics · Physics 2016-05-10 V. A. Vladimirov

In this paper we continue our work on adaptive timestep control for weakly non- stationary problems. The core of the method is a space-time splitting of adjoint error representations for target functionals due to S\"uli and Hartmann. The…

Numerical Analysis · Mathematics 2014-06-19 Christina Steiner , Siegfried Müller , Sebastian Noelle

Boundary integral methods are attractive for solving homogeneous linear constant coefficient elliptic partial differential equations on complex geometries, since they can offer accurate solutions with a computational cost that is linear or…

Numerical Analysis · Mathematics 2023-01-25 Fredrik Fryklund , Sara Pålsson , Anna-Karin Tornberg