In this lecture we provide two examples of problems where reasonable models are given by the deterministic continuum limit of the discrete random walk through which the problem is naturally defined. Once suitably defined, this continuum limit usually takes the form of a partial differential equation (hence deterministic). One interesting use of the continuum limit we will see in upcoming lectur...

Single-particle resonant-states in the continuum are determined by solving scattering states of the Dirac equation with proper asymptotic conditions in the relativistic mean field theory (RMF). The regular and irregular solutions of the Dirac equation at a large radius where the nuclear potentials vanish are relativistic Coulomb wave functions, which are calculated numerically. Energies, widths...

There have been many attempts to derive continuum models for dense granular flow, but a general theory is still lacking. Here, we start with Mohr-Coulomb plasticity for quasi-two-dimensional granular materials to calculate (average) stresses and slip planes, but we propose a "stochastic flow rule" (SFR) to replace the principle of coaxiality in classical plasticity. The SFR takes into account t...

In this note, we provide a new characterization of Aldous’ Brownian continuum random tree as the unique fixed point of a certain natural operation on continuum trees (which gives rise to a recursive distributional equation). We also show that this fixed point is attractive.

The purpose of this study is to investigate the dynamic response of axially translating continua undergoing both the effect of friction and axial acceleration. The axially moving continuum is initially modeled as a string, neglecting its flexural stiffness; the response, with particular interest given to transverse vibrations and dynamic stability, is studied through numerical methods. A finite...

The Hirota equation is a higher order extension of the nonlinear Schrödinger equation by incorporating third order dispersion and one form of self steepening effect. New periodic waves for the discrete Hirota equation are given in terms of elliptic functions. The continuum limit converges to the analogous result for the continuous Hirota equation, while the long wave limit of these discrete per...

in this paper, the dynamic simulation for a high pressure regulator is performed to obtain the regulator behavior. to analyze the regulator performance, the equation of motion for inner parts, the continuity equation for diverse chambers and the equation for mass flow rate were derived. because of nonlinearity and coupling, these equations are solved using numerical methods and the results are ...

In order to study the mechanical behaviour of polar ice masses, the method of continuum mechanics is used. The newly developed CAFFE model (Continuum-mechanical, Anisotropic Flow model, based on an anisotropic Flow Enhancement factor) is described, which comprises an anisotropic flow law as well as a fabric evolution equation. The flow law is an extension of the isotropic Glen’s flow law, in wh...

We use renormalization group methods to derive equations of motion for large scale variables in uid dynamics. The large scale variables are averages of the underlying continuum variables over cubic volumes, and naturally live on a lattice. The resulting lattice dynamics represents a perfect discretization of continuum physics, i.e. grid artifacts are completely eliminated. Perfect equations of ...

In an early approach, we proposed a kinetic model with multiple translational temperature [K. Xu, H. Liu and J. Jiang, Phys. Fluids 19, 016101 (2007)] to simulate non-equilibrium flows. In this paper, instead of using three temperatures in the x−, y−, and z-directions, we further define the translational temperature as a second-order symmetric tensor. Based on a multiple stage BGK-type collisio...