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We study the time-dependent Navier-Stokes equations in the context of stochastic finite element discretizations. Specifically, we assume that the viscosity is a random field given in the form of a generalized polynomial chaos expansion, and…

Numerical Analysis · Mathematics 2026-01-14 Bedřich Sousedík , Randy Price

Fractional diffusion equations replace the integer-order derivatives in space and time by their fractional-order analogues. They are used in physics to model anomalous diffusion. This paper develops strong solutions of space-time fractional…

Probability · Mathematics 2016-12-19 Zhen-Qing Chen , Mark M. Meerschaert , Erkan Nane

Fractional diffusion equations for three-dimensional lattice models based on fractional-order differences of the Grunwald-Letnikov type are suggested. These lattice fractional diffusion equations contain difference operators that describe…

Statistical Mechanics · Physics 2015-03-13 Vasily E. Tarasov

A general fractional relaxation equation is considered with a convolutional derivative in time introduced by A. Kochubei (Integr. Equ. Oper. Theory 71 (2011), 583-600). This equation generalizes the single-term, multi-term and…

Analysis of PDEs · Mathematics 2018-12-26 Emilia Bazhlekova

The purpose of this paper is to provide new formulas for the effective diffusion coefficient of a generalized Fick-Jacobs equation for narrow 3-dimensional channels. The generalized Fick-Jacobs equation is obtained by projecting the…

Mathematical Physics · Physics 2014-12-01 Carlos Valero Valdes , Rafael Herrera Guzman

We investigate superconvergence properties of the spectral interpolation involving fractional derivatives. Our interest in this superconvergence problem is, in fact, twofold: when interpolating function values, we identify the points at…

Numerical Analysis · Mathematics 2015-03-25 Xuan Zhao , Zhimin Zhang

We introduce a general coupled system of parabolic equations with quadratic nonlinear terms and diffusion terms defined by fractional powers of the Laplacian operator. We develop a method to establish the rigorous convergence of the…

Analysis of PDEs · Mathematics 2024-12-25 Oscar Jarrin , Geremy Loachamin

We present a full space-time numerical solution of the advection-diffusion equation using a continuous Galerkin finite element method on conforming meshes. The Galerkin/least-square method is employed to ensure stability of the discrete…

Numerical Analysis · Mathematics 2024-11-25 Biswajit Khara , Kumar Saurabh , Robert Dyja , Anupam Sharma , Baskar Ganapathysubramanian

In this paper a finite difference/local discontinuous Galerkin method for the fractional diffusion-wave equation is presented and analyzed. We first propose a new finite difference method to approximate the time fractional derivatives, and…

Numerical Analysis · Mathematics 2015-07-29 Leilei Wei

By using the Zubarev nonequilibrium statistical operator method, and the Liouville equation with fractional derivatives, a generalized diffusion equation with fractional derivatives is obtained within the Renyi statistics. Averaging in…

Statistical Mechanics · Physics 2016-09-21 P. Kostrobij , B. Markovych , O. Viznovych , M. Tokarchuk

This paper analyzes the convergence of a Petrov-Galerkin method for time fractional wave problems with nonsmooth data. Well-posedness and regularity of the weak solution to the time fractional wave problem are firstly established. Then an…

Numerical Analysis · Mathematics 2024-12-20 Hao Luo , Binjie Li , Xiaoping Xie

We survey some results on Lipschitz and Schauder regularity estimates for viscous Hamilton--Jacobi equations with subcritical L\'evy diffusions. The Schauder estimates, along with existence of smooth solutions, are obtained with the help of…

Analysis of PDEs · Mathematics 2024-03-07 Espen R. Jakobsen , Artur Rutkowski

We propose a fourth-order unfitted characteristic finite element method to solve the advection-diffusion equation on time-varying domains. Based on a characteristic-Galerkin formulation, our method combines the cubic MARS method for…

Numerical Analysis · Mathematics 2022-06-09 Chuwen Ma , Qinghai Zhang , Weiying Zheng

This paper presents the first analysis of a space--time hybridizable discontinuous Galerkin method for the advection--diffusion problem on time-dependent domains. The analysis is based on non-standard local trace and inverse inequalities…

Numerical Analysis · Mathematics 2023-07-06 Keegan L. A. Kirk , Tamas L. Horvath , Aycil Cesmelioglu , Sander Rhebergen

Fractional derivatives can be used to model time delays in a diffusion process. When the order of the fractional derivative is distributed over the unit interval, it is useful for modeling a mixture of delay sources. In some special cases…

Analysis of PDEs · Mathematics 2016-11-29 Jebessa B. Mijena , Erkan Nane

A matrix method for the solution of direct fractional Sturm-Liouville problems on bounded domain is proposed where the fractional derivative is defined in the Riesz sense. The scheme is based on the application of the Galerkin spectral…

Numerical Analysis · Mathematics 2017-04-06 Paolo Ghelardoni , Cecilia Magherini

In this paper we study generalized time-fractional diffusion equations on the Poincar\`e half plane $\mathbb{H}_2^+$. The time-fractional operators here considered are fractional derivatives of a function with respect to another function,…

Mathematical Physics · Physics 2020-07-24 R. Garra , F. Maltese , E. Orsingher

We formulate a stabilized quasi-optimal Petrov-Galerkin method for singularly perturbed convection-diffusion problems based on the variational multiscale method. The stabilization is of Petrov-Galerkin type with a standard finite element…

Numerical Analysis · Mathematics 2016-06-16 Guanglian Li , Daniel Peterseim , Mira Schedensack

This paper is dedicated to addressing the simultaneous inversion problem involving the initial value and space-dependent source term in a time-fractional diffusion-wave equation. Firstly, we establish the uniqueness of the inverse problem…

Numerical Analysis · Mathematics 2025-02-25 Yun Zhang , Xiaoli Feng , Xiongbin Yan

In this paper, a higher order finite difference scheme is proposed for Generalized Fractional Diffusion Equations (GFDEs). The fractional diffusion equation is considered in terms of the generalized fractional derivatives (GFDs) which uses…

Numerical Analysis · Mathematics 2022-06-08 Kamlesh Kumar , Rajesh K. Pandey