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Many physical systems of interest involve the close interaction of a flow in a domain with complex, time-varying boundaries. Treatment of boundaries of this nature is cumbersome due to the difficulty in explicitly tracking boundaries that…

Fluid Dynamics · Physics 2025-02-25 Emma M. Boyd , Eric Sandall , Maycon Meier , J. Matt Quinlan , Brandon Runnels

We study the anisotropic boundary conditions for the dilute O(n) loop model with the methods of 2D quantum gravity. We solve the problem exactly on a dynamical lattice using the correspondence with a large $N$ matrix model. We formulate the…

High Energy Physics - Theory · Physics 2015-05-14 Jean-Emile Bourgine , Kazuo Hosomichi , Ivan Kostov

We consider the simulation of isentropic flow in pipelines and pipe networks. Standard operating conditions in pipe networks suggest an emphasis to simulate low Mach and high friction regimes -- however, the system is stiff in these regimes…

Numerical Analysis · Mathematics 2025-07-22 Michael Redle , Michael Herty

We give sharp conditions for the large time asymptotic simplification of aggregation-diffusion equations with linear diffusion. As soon as the interaction potential is bounded and its first and second derivatives decay fast enough at…

Analysis of PDEs · Mathematics 2021-05-28 José A. Carrillo , David Gómez-Castro , Yao Yao , Chongchun Zeng

On the basis of generalization of upper and lower solution method to the singular two point boundary value problems, the existence theorem of solutions for the system, which models a process of magnetic insulation in plasma is proved.

Mathematical Physics · Physics 2007-05-23 A. V. Sinitsyn

We consider a parameter dependent family of damped hyperbolic equations with interesting limit behavior: the system approaches steady states exponentially fast and for parameter to zero the solutions converge to that of a parabolic limit…

Numerical Analysis · Mathematics 2017-04-19 Herbert Egger , Thomas Kugler

We present a meshfree generalized finite difference method for solving Poisson's equation with a diffusion coefficient that contains jump discontinuities up to several orders of magnitude. To discretize the diffusion operator, we formulate…

Numerical Analysis · Mathematics 2022-09-23 Heinrich Kraus , Jörg Kuhnert , Andreas Meister , Pratik Suchde

A fluid description for collisionless magnetized plasmas that takes into account the effect of cyclotron resonance has been developed. Following the same approach as the Landau fluid closure, the heat flux components associated with…

Plasma Physics · Physics 2021-04-13 Taiki Jikei , Takanobu Amano

We derive asymptotic formulas for the solutions of the mixed boundary value problem for the Poisson equation on the union of a thin cylindrical plate and several thin cylindrical rods. One of the ends of each rod is set into a hole in the…

Analysis of PDEs · Mathematics 2019-02-20 R. Bunoiu , G. Cardone , S. A. Nazarov

Condition imposed on the nonlinear terms of a nonlinear diffusion equation with {R}obin boundary condition is the main focus of this paper. The degenerate parabolic equations, such as the {S}tefan problem, the {H}ele--{S}haw problem, the…

Analysis of PDEs · Mathematics 2018-02-09 Taishi Motoda , Takeshi Fukao

We consider the local well-posedness of the one-dimensional nonisentropic Euler equations with moving physical vacuum boundary condition. The physical vacuum singularity requires the sound speed to be scaled as the square root of the…

Analysis of PDEs · Mathematics 2019-05-29 Yongcai Geng , Yachun Li , Dehua Wang , Runzhang Xu

Motivated by porous medium equations with randomly perturbed velocity field, this paper considers a class of nonlinear degenerate diffusion equations with nonlinear conservative noise in bounded domains. The existence, uniqueness and…

Probability · Mathematics 2023-09-06 Kai Du , Ruoyang Liu , Yuxing Wang

We study the long-time asymptotics of prototypical non-linear diffusion equations. Specifically, we consider the case of a non-degenerate diffusivity function that is a (non-negative) polynomial of the dependent variable of the problem. We…

Analysis of PDEs · Mathematics 2020-08-13 Ivan C. Christov , Akif Ibraguimov , Rahnuma Islam

A procedure that allows study of unstable stability of a boundary layer between plasma and a magnetic field has been developed. Layer equilibrium for one reason or another is not set but follows from strict solution of kinetic equation with…

Plasma Physics · Physics 2010-05-25 V. V. Lyahov , V. M. Neshchadim

The main aim of this paper is to document the performance of $p$-refinement with respect to maximum principles and the non-negative constraint. The model problem is (steady-state) anisotropic diffusion with decay (which is a second-order…

Numerical Analysis · Computer Science 2015-03-19 G. S. Payette , K. B. Nakshatrala , J. N. Reddy

Highly accurate simulation of plasma transport is needed for the successful design and operation of magnetically confined fusion reactors. Unfortunately, the extreme anisotropy present in magnetized plasmas results in thin boundary layers…

Numerical Analysis · Mathematics 2023-06-30 Christopher J. Vogl , Ilon Joseph , Milan Holec

A weak Galerkin discretization of the boundary value problem of a general anisotropic diffusion problem is studied for preservation of the maximum principle. It is shown that the direct application of the $M$-matrix theory to the stiffness…

Numerical Analysis · Mathematics 2015-07-20 Weizhang Huang , Yanqiu Wang

We study the isotropization of a homogeneous, strongly coupled, non-Abelian plasma by means of its gravity dual. We compare the time evolution of a large number of initially anisotropic states as determined, on the one hand, by the full…

High Energy Physics - Theory · Physics 2012-05-22 Michal P. Heller , David Mateos , Wilke van der Schee , Diego Trancanelli

A self-consistent model is presented for performing steady-state fully kinetic Particle-in-Cell simulations of magnetised plasma plumes. An energy-based electron reflection prevents the numerical pump instability associated with a typical…

Plasma Physics · Physics 2022-02-23 Shaun Andrews , Simone Di Fede , Mirko Magarotto

A modified Poisson-Nernst-Planck system in a bounded domain with mixed Dirichlet-Neumann boundary conditions is analyzed. It describes the concentrations of ions immersed in a polar solvent and the correlated electric potential due to the…

Analysis of PDEs · Mathematics 2023-05-25 Ansgar Jüngel , Annamaria Massimini