各向加权异性有限元法在不可压粘性流动计算中的应用

本文利用各向异性张力有限单元，考虑到其独特的性质，提出了一种各向加权异性的算法，即在不同方向采用不同连续性的插值函数，然后再在原连续性较弱的方向以连续性较强的插值函数计算，最后把两次计算的结果加权处理。这种方法可以适应两个方向连续性要求不同或相同的各种情况，即克服了一般各向异性张力有限单元的局限性，又大大减少了存贮量和计算量。     

Issues in the estimation and application of latent structure models of choice

Our paper provides a brief review and summary of issues and advances in the use of latent structure and other finite mixture models in the analysis of choice data. Focus is directed to three primary areas: (1) estimation and computational issues, (2) specification and interpretation issues, and (3) future research issues. We comment on what latent structure models have promised, what has been, to date, delivered, and what we should look forward to in the future.     

铝电解槽磁流体稳定性有限元分析

本文采用有限元法求解分层磁流体小扰动方程系统特征值，研究铝电解槽稳定性。研究结果表明，在没有电磁力时，铝液表面波动（内波）是稳定的。存在电磁力时，它会激发铝液表面波动的某些低频长波分量不稳定性，高频短波不受影响。被激发的不稳定波动频率和扰动增长率与电流密度，磁感应强度垂直分量，铝电解槽长宽比，电解质和铝液的密度差，厚度等因素密切相关。减少电流密度，磁感应强度，增加电极距离和铝液厚度可以提高铝电解槽的稳定性。这对铝电解槽优化设计和在线控制有重要意义。     

隔河岩重力拱坝拱座深层处理平面有限元分析

清江隔河岩重力拱坝坝基地质条件复杂，软弱夹层，断裂构造多，岩溶发育，两岸拱座存在局部滑动问题。     

Simulation of leachate migration in leaky aquifers

A two-dimensional cross-section finite difference model is presented to simulate density dependent leachate migration in leaky aquifers. Unlike existing models, a new approach is adopted to couple the groundwater-flow equation and the hydrodynamic dispersion equation with the elimination of the intermediate step of calculating velocities. The concept of the reference density is employed, permitting increased accuracy (over pressure-based models) in the representation of the transport process. The model is then used to study the effect of several hydraulic and transport parameters on the flow pattern and plume migration which are found to be very sensitive to most of these parameters. Equiconcentration and equipotential lines are overlapped to provide a better understanding of the coupling effect.     

浍河水库泄洪洞结构优化研究

根据有限元计算原理，结合山西临汾地区浍河水库泄洪洞，对土坝下的大型软基涵洞分层填土施工过程和蓄水对结构的影响进行了模拟计算，得到了更贴近实际的涵洞结构内力和涵洞土压力分布规律，并根据实际地基条件及现有涵洞的两种常见的结构形态对涵洞结构形式进行了优化，其成果已用于设计和施工，证明了该研究方法的科学性和结论的正确性。     

Application of a Three-dimensional Wind Driven Circulation Model to Assess the Locations of New Drinking Water Intakes in Lake Ontario

A 3D transport model is used to perform a comparative analysis of several potential drinking water intakes located along the northwest shore of Lake Ontario between Toronto and Oshawa. The model is specifically used to assess each intake under both long- and short-term transport of a potential pollutant release from the Pickering Nuclear Generating Station and potential and actual pollutant releases from local land sources respectively. A model based on a 500 m grid resolution is calibrated using data collected in the aftermath of the 1992 tritium spill at the Pickering Nuclear Generation Station and subsequently used to simulate long-term transport. A model based on a 100 m grid resolution is verified using drogue studies and used to simulate short-term transport events. Both models are used to assess pollutant levels at each of nine potential intake locations under different wind scenarios and pollutant releases. Field data for the study included water quality and flow measurements from local sewers and rivers, and estimates of pollutant levels from the local waste water treatment plants. This paper describes the model setup for both the long-term and short-term transport models, calibration using field data, long-term transport modeling, short-term transport modeling, and the comprehensive analysis approach used to evaluate the nine potential intake locations proposed. Results indicated that four intakes in particular outperformed other intake locations by maintaining bottom pollutant levels within governmental standards and warning times that exceeded 20 hours.     

软土地层中盾构法开挖三维有限元模拟

以某条软土地层中开挖的地铁隧道为例,根据非线性有限元法的基本原理,利用大型非线性有限元软件ADINA三维动态模拟地铁隧道开挖过程,计算结果揭示了在盾构推进过程中地表沉降分布以及特点,得到盾构法开挖引起的地表沉降曲线,其形态与Peck计算得出的横向地表沉降槽正态分布曲线的形态基本一致,隧道轴线正上方地表沉降最为明显。     

影响长廊阻抗式调压室配筋的几个因素分析

采用三维非线性有限元方法,对四川天全县干溪坡水电站调压室结构特性进行研究,并对几个影响配筋的因素进行敏感性分析,得出各个因素对配筋结果的影响,为调压室结构设计提供科学依据。