井巷紊流传质的数学模型及紊流弥散系数

本文根据质量守恒定律、Fick第一扩散定律和Boussinesq假设导出了井巷污染物紊流传质的通用数学模型及纵向(?)散模型。针对井巷各种污染源的不同释放规律给出了九种源函数,从理论上导出了井巷污染物紊流传质过程的紊流(?)散系数,其大小与井巷摩擦阻力系数的平方根、井巷水力半径和断面平均风速成正比,还给出了弥散模型的通解,指出井巷紊流传质的实验研究必须满足Reynolds相似。     

赣南红色旅游资源特征分析及开发策略

赣南红色旅游资源极为丰富，具有极好的品牌优势、市场优势和资源整合优势。目前，赣南红色旅游还存在人气指数不高、资源整合力度不强、规划滞后、促销手段落后、管理体制不完善等制约因素。对此，应抓住机遇，加快制定规划，理顺管理体制，提高旅游管理水平。要正确处理好红色旅游资源开发与保护的关系。要精心打造赣南红色旅游品牌，整合各种旅游资源，延伸红色旅游产品的内涵，努力将赣南红色旅游发展成为政治经济文化社会全面协调发展的和谐工程。     

浙江道教史发凡

浙江在道教史上涌现出了一大批著名道士、宗派领袖、思想家,一大批籍贯不是浙江的道教学者、思想家和著名道士也长期在浙江传道、讲学,他们的行为与思想构成了浙东学派诞生的部分前奏和思想背景,其影响使得浙东学派形成了一些独到的特点和富于特色的面貌。浙江目前仍保存有众多的道教历史遗迹。这两方面说明,浙江当之无愧地可以称为道教大省。在历史上,浙江道教注重道、学、术的紧密结合,观念开放,态度务实、灵活,注重创新,长于著述,注重文献的保存、继承与阐述,对中国道教和传统文化有重大的贡献;现在它正在发展中。可以相信,它在未来能取得更好的发展。     

Bose-Einstein-type distribution applied to flicker noise and turbulence

We treat flicker noise in arbitrary structures and turbulence as vortical flicker noise. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 149, No. 2, pp. 318–319, November, 2006.     

The modeling of small scales in two-dimensional turbulent flows: A statistical mechanics approach

In previous work we have defined statistical equilibrium states for 2D incompressible Euler equations. We study here the relaxation process toward equilibrium. This leads to a natural modeling of the small scales in turbulent flows, which might be relevant for meteorological and oceanographic applications. Numerical simulations illustrating the performance of these new models are presented.     

Efficient computation of mean drag for the subcritical flow past a circular cylinder using general Galerkin G2

General Galerkin (G2) is a new computational method for turbulent flow, where a stabilized Galerkin finite element method is used to compute approximate weak solutions to the Navier–Stokes equations directly, without any filtering of the equations as in a standard approach to turbulence simulation, such as large eddy simulation, and thus no Reynolds stresses are introduced, which need modelling. In this paper, G2 is used to compute the drag coefficient c_D for the flow past a circular cylinder at Reynolds number Re=3900, for which the flow is turbulent. It is found that it is possible to approximate c_D to an accuracy of a few percent, corresponding to the accuracy in experimental results for this problem, using less than 10⁵ mesh points, which makes the simulations possible using a standard PC. The mesh is adaptively refined until a stopping criterion is reached with respect to the error in a chosen output of interest, which in this paper is c_D. Both the stopping criterion and the mesh‐refinement strategy are based on a posteriori error estimates, in the form of a space–time integral of residuals times derivatives of the solution of a dual problem, linearized at the approximate solution, and with data coupling to the output of interest. Copyright © 2008 John Wiley & Sons, Ltd.     

Simple Singularities for Hamilton-Jacobi Equations with Max-Concave Hamiltonians and Generalized Characteristics

We consider piecewise smooth viscosity solutions to a Hamilton-Jacobi equation, for which the Hamiltonian is the maximum of a finite number of smooth concave functions. We describe the possible types of “basic” singularities, namely jump discontinuities in either the derivative of the solution or the Hamiltonian, which occur across a smooth hypersurface. Each such type of singularity is described in terms of the properties of the Hamiltonian and the classical characteristics in the regions on either side of the singularity. Where appropriate, singular characteristic equations of the types developed by Melikyan are formulated which can be used in constructions.     

Chaos,transport and mesh convergence for fluid mixing

Chaotic mixing of distinct fluids produces a convoluted structure to the interface separating these fluids. For miscible fluids （as considered here）, this interface is defined as a 50% mass concentration isosurface. For shock wave induced （Richtmyer-Meshkov） instabilities, we find the interface to be increasingly complex as the computational mesh is refined. This interfacial chaos is cut off by viscosity, or by the computational mesh if the Kolmogorov scale is small relative to the mesh. In a regime of converged interface statistics, we then examine mixing, i.e. concentration statistics, regularized by mass diffusion. For Schmidt numbers significantly larger than unity, typical of a liquid or dense plasma, additional mesh refinement is normally needed to overcome numerical mass diffusion and to achieve a converged solution of the mixing problem. However, with the benefit of front tracking and with an algorithm that allows limited interface diffusion, we can assure convergence uniformly in the Schmidt number. We show that different solutions result from variation of the Schmidt number. We propose subgrid viscosity and mass diffusion parameterizations which might allow converged solutions at realistic grid levels.     

Multistable current–voltage characteristics a fingerprints of growth-related imperfections in semiconductor superlattices

The influence of imperfections and growth-related disorder on the current–voltage characteristics of doped superlattices is investigated theoretically. It is demonstrated that the location of a defect can be directly identified from the current measurements. Such measurements can also be used as an estimate for the degree of microscopic disorder.