High‐order finite elements applied to the discrete Boltzmann equation

A discontinuous Galerkin approach for solving the discrete Boltzmann equation is presented, allowing to compute approximate solutions for fluid flow problems. Based on a two‐dimensional high‐order finite element and an explicit Euler time stepping scheme, the D2Q9 model is discretized and the results are compared to the exact solution of the Navier–Stokes equation. Four numerical examples are considered, including stationary and instationary problems with curved boundaries. It is demonstrated that the proposed method allows to obtain the desired, highly efficient exponential convergence. Copyright © 2006 John Wiley & Sons, Ltd.     

紫木凼金矿矿石工艺性质研究

紫木凼金矿石是黔西南地区较典型的难处理金矿石。矿石工艺性质研究的重点是查明金矿物在矿石中的赋存状态、嵌布粒度等工艺特性；同时，对矿石物质组成，特别是对选冶工艺有害成分的矿物也进行了系统研究。该研究的主要目的是为原矿沸腾焙烧一氰化提金工艺试验提供依据。     

立式行星磨磨腔内流场的三维数值模拟

针对立式行星磨磨腔内流场的特点,运用计算流体力学方法对磨腔内流场进行三维分析。根据模拟结果,首次提出磨腔内流场结构特点,得到流场的速度场和压力场,为进一步分析被磨物料在磨腔内的运动和磨辊密封结构的设计提供理论基础。     

池式反应堆堆内流场数值模拟

以板型燃料组件池式反应堆为研究对象,采用计算流体动力学程序CFX5对堆内流场进行了数值模拟,结果表明:流过堆芯燃料组件的流速较大,在燃料组件出口位置流速达到最大值;无论是否带有围桶,堆内压降均主要集中在堆芯燃料组件上,入口流量增大,堆芯燃料组件上的压降随之增加;堆芯上部腔室和下部腔室的压力变化很小;在相同的入口流量下,带与不带围桶的堆芯进出口差压非常接近。     

Starting solutions for some unsteady unidirectional flows of a second grade fluid

Exact solutions corresponding to the motions of a second grade fluid, due to the cosine and sine oscillations of an infinite flat plate as well as those induced by an oscillating pressure gradient are determined by means of the Fourier sine transforms. These solutions, presented as sum of the steady-state and transient solutions, satisfy both the governing equations and all associate initial and boundary conditions. In the special case when α₁ → 0, they reduce to those for a Navier-Stokes fluid.     

圆管临界热流密度的流体模化

为了评价现有的临界热流密度(CHF)流体模化技术,在氟里昂-12热工实验装置上完成了φ202.5圆管CHF实验。在此基础上,用不同的数据源,比较了Ahmad补偿失真模型、鲁钟琪模型、Groeneveld模型和Stevens-Kirby经验比例因子模型的预测精度和适用范围,为复杂流道中的CHF流体模化研究奠定了基础。     

Rare earth elements in CO_2-fluid inclusions in mantle Iherzolite

Trace elements including REE (Rare Earth Elements) in fluid inclusions in Iherzolite, olivine, orthopyroxene, and clinopyroxene have been determined by heating-decrepitation and ICP-MS (Element Type Inductively Coupled Plasma-Mass Spectrometry) method. Normalized CO2 fluid/chondrite data show that mantle fluids are rich in REEs, especially LREEs (Light Rare Earth Elements), several times or dozen times higher than mantle rocks and mantle minerals. There are close relationships among the REE data of olivine, orthopyroxene, clinopyroxene and 1herzolite. Compared to the data of chemical dissolution method, it is believed that REE data obtained from heating-decrepitation and ICP-MS technique are contributed by CO2 fluid inclusions. About 60% (mass fraction) of tiny inclusions are observed not to be decrepitated above 1000℃, so REE data obtained are only contributed by decrepitated inclusions. Mantle fluids rich in LREE play an important role in mantle metasomatism, partial melting and mineralization.     

Solving a Nonlinear Problem in Magneto-Rheological Fluids Using the Immersed Interface Method

Many applications lead to a nonlinear elliptic interface problem in which the discontinuous coefficient depends on the solution and the material properties. A finite difference method based on Cartesian grids and the maximum principle preserving immersed interface method is proposed for the nonlinear elliptic interface problems discussed in this paper. Numerical experiments against the exact solutions reveal that our method is nearly second order accurate in the infinity norm. The method is applied to study the magneto-rheological field-responsive fluids that contain iron particles. Numerical experiments are performed against the results from the literature.     

油压减振器计算机辅助优化设计系统的研制

为了优化可调式线性油压减振器的性能，在白行研制的广义优化设计支持平台上对其线性阻尼系统进行广义优化建模与设计，并基于MATLAB开发了动态仿真软件包，对该广义优化设计结果进行分析与评价．样机开发与试验研究结果表明：文中建立的广义优化设计数学模型和动态仿真模型是准确的，研制的计算机辅助优化设计系统高效、实用．     

Perturbation Analysis of Multiclass Stochastic Fluid Models

We use a stochastic fluid model (SFM) to capture the operation of finite-capacity queueing systems with multiple customer classes. We derive gradient estimators for class-dependent loss and workload related performance metrics with respect to any one of several threshold parameters used for buffer control. These estimators are shown to be unbiased and directly observable from a sample path without any knowledge of underlying stochastic characteristics of the traffic processes. This renders them computable in on-line environments and easily implementable in settings such as communication networks.