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In this paper we investigate the variable coefficient two-sided fractional diffusion, advection, reaction equations on a bounded interval. It is known that the fractional diffusion operator may lose coercivity due to the variable…

Numerical Analysis · Mathematics 2022-03-23 Xiangcheng Zheng , V. J. Ervin , Hong Wang

The equation which describes a particle diffusing in a logarithmic potential arises in diverse physical problems such as momentum diffusion of atoms in optical traps, condensation processes, and denaturation of DNA molecules. A detailed…

Statistical Mechanics · Physics 2015-06-03 Ori Hirschberg , David Mukamel , Gunter M. Schütz

We study existence and stability of travelling waves for nonlinear convection diffusion equations in the 1-D Euclidean space. The diffusion coefficient depends on the gradient in analogy with the p-Laplacian and may be degenerate.…

Analysis of PDEs · Mathematics 2017-05-17 Eduard Feireisl , Danielle Hilhorst , Hana Petzeltova , Peter Takac

A numerical method to solve the fractional diffusion equation, which could also be easily extended to many other fractional dynamics equations, is considered. These fractional equations have been proposed in order to describe anomalous…

Numerical Analysis · Mathematics 2025-10-20 S. B. Yuste , L. Acedo

A computational fluid model is developed to study waves and instabilities. A new technique involving initial perturbations in configuration space have been implemented to excite the plasma waves; i.e. the perturbations acting similar to a…

Plasma Physics · Physics 2007-05-23 H. Hakimi Pajouh , M. R. Rouhani , H. Abbasi , F. Kazeminejad , S. Rouhani

Inertial particles in turbulent flows are characterised by preferential concentration and segregation and, at sufficient mass loading, dense particle clusters may spontaneously arise due to momentum coupling between the phases. These…

Fluid Dynamics · Physics 2019-01-30 Alessio Innocenti , Rodney O Fox , Sergio Chibbaro

We present several results on smoothness in $L_{p}$ sense of filtering densities under the Lipschitz continuity assumption on the coefficients of a partially observable diffusion processes. We obtain them by rewriting in divergence form…

Probability · Mathematics 2009-08-14 N. V. Krylov

In confined plasmas, a localized fluctuation in a marginal or weakly damped region will propagate and generate an avalanche if it exceeds a threshold. In this letter, a new model for turbulence spreading based on subcritical instability in…

Plasma Physics · Physics 2019-03-27 R. A. Heinonen , P. H. Diamond

We consider the initial/boundary value problem for a diffusion equation involving multiple time-fractional derivatives on a bounded convex polyhedral domain. We analyze a space semidiscrete scheme based on the standard Galerkin finite…

Numerical Analysis · Mathematics 2015-06-18 Bangti Jin , Raytcho Lazarov , Yikan Liu , Zhi Zhou

The practice-based learning methodologies offer to undergraduate professors different ways to illustrate certain general physic principles. Traditional experimental workbenches have been extensively used during decades for academic lessons…

In this study we present an extension of the replicator equation with diffusion to multiplex graphs. We derive an exact formula for the diffusion term, which shows that, while diffusion is linear for numbers of agents, it is necessary to…

Physics and Society · Physics 2016-08-10 Rubén J. Requejo , Albert Díaz Guilera

A new method is proposed to numerically extract the diffusivity of a (typically nonlinear) diffusion equation from underlying stochastic particle systems. The proposed strategy requires the system to be in local equilibrium and have…

Statistical Mechanics · Physics 2018-05-09 Peter Embacher , Nicolas Dirr , Johannes Zimmer , Celia Reina

The scattering of inertia-gravity waves by large-scale geostrophic turbulence in a rapidly rotating, strongly stratified fluid leads to the diffusion of wave energy on the constant-frequency cone in wavenumber space. We derive the…

Atmospheric and Oceanic Physics · Physics 2019-05-22 Hossein Kafiabad , Miles A. C. Savva , Jacques Vanneste

A new method that enables easy and convenient discretization of partial differential equations with derivatives of arbitrary real order (so-called fractional derivatives) and delays is presented and illustrated on numerical solution of…

Numerical Analysis · Mathematics 2009-03-06 Igor Podlubny , Aleksei V. Chechkin , Tomas Skovranek , YangQuan Chen , Blas M. Vinagre Jara

We present an extended version of an invited talk given on the International Conference "Turbulent Mixing and Beyond". The dynamical and statistical description of stably stratified turbulent boundary layers with the important example of…

Fluid Dynamics · Physics 2009-02-18 Victor S. L'vov , Itamar Procaccia , Oleksii Rudenko

We develop unified and easy to use framework to study robust fully discrete numerical methods for nonlinear degenerate diffusion equations $$ \partial_t u-\mathfrak{L}[\varphi(u)]=f(x,t) \qquad\text{in}\qquad \mathbb{R}^N\times(0,T), $$…

Numerical Analysis · Mathematics 2018-10-17 Félix del Teso , Jørgen Endal , Espen R. Jakobsen

This is an idiosyncratic survey of statistical fluid mechanics centering on the Hopf functional differential equation. Using the Burgers equation for illustration we review several functional integration approaches to theory of turbulence.…

Fluid Dynamics · Physics 2022-02-16 Koji Ohkitani

Simulations are made of a probe particle diffusing through a complex fluid. Probe particle motions are described by the Mori-Zwanzig equation and Mori's orthogonal hierarchy of random forces scheme, subject to the approximation that the…

Soft Condensed Matter · Physics 2014-06-20 George D. J. Phillies

In this note we consider a family of nonlinear (conditional) expectations that can be understood as a multidimensional diffusion with uncertain drift and certain volatility. Here, the drift is prescribed by a set-valued function that…

Probability · Mathematics 2023-11-14 David Criens , Lars Niemann

In the paper, we discuss the studies of mathematical models of diffusion scattering of waves in the phase space, and relation of these models with quantum mechanics. In the previous works it is shown that in these models of classical…

Mathematical Physics · Physics 2016-03-22 E. M. Beniaminov