向家坝水垫塘的实验研究与数值模拟

多股水平淹没射流消力池的大量试验研究结果表明：泄槽的体形以等宽或微收缩为宜；水平方向窄而垂直方向厚的水舌适应水位变化的稳定性较好，能始终保持水平淹没射流状态；表、中孔的最优坎高差应大于中孔水流的主流水深，以使表层水跃的回流漩滚区向两侧表孔溢流面充分扩散，从而减弱或消除中孔表层水跃的横轴漩滚。用三维RNG k—ε紊流模型进行了数值模拟，将计算的消力池底板压强及水深与试验结果进行了对比，两者符合较好。     

土石坝施工仿真模拟中坝面填筑系统的初步研究

阐述了坝面填筑系统在土石坝施工仿真模拟中的作用、仿真原理及约束条件,对土石坝施工仿真中气象因素的影响进行了分析,并提出了解决方案。     

TWO-DIMENSIONAL SIMULATION OF FLOWS IN PLANE-WALL DIFFUSERS

A numerical model has been developed for computing turbulent flow in plane-walldiffuser.The model solves the weakly compressible flow equations with the application of theSmagorinsky's subgrid-scale turbulence model and the boundary conditions of partial slip and noslip at the solid wall.Application examples include two-dimensional calculations of unstalled andstalled flows in diffusers of small diverging angle,as well as transitory stall flow in a symmetricdiffuser of 16°total angle.For the unstalled and stalled flows,the calculated pressure recoveryand velocity profile are compared with experimental data.For the transitory stall flow,the com-putational result shows the unsteady flow features including the vortex shedding and stallwashout phenomena that have been experimentally observed.     

下游为干河床的溃坝水流数值模拟

应用二阶TVD—MacCormack格式计算了含间断波的二维浅水流动．模拟算例为下游是干河床、瞬间部分坝体溃决形成的溃坝水流运动．针对该格式，采用恰当的限制器使得解既不产生过大耗散，又具有高分辨率．     

MATLAB在反向地球化学模拟中的应用

为了研究地下水的地球化学演化,根据能量最低原则和化学热力学的基本原理建立了数学模型,利用MATLAB优化工具箱提供的函数linprog对模型进行了求解。MATLAB优化工具箱输入简单,可以准确、快速地求解线性规划问题的最优解和目标函数。     

绿色建筑采光模拟软件的适用性分析与计算精度验证

建筑采光模拟软件对绿色建筑设计有不可或缺的作用.文章首先阐述了建筑采光模拟软件的种类及特性,然后对4款采光软件的适用性进行分析,最后选取3款适用性较强的软件,通过实测与模拟对比的方法验证了软件的计算精度.     

浅谈税法课程改革的必要性以及存在的问题

针对目前税法课程教学效果不佳的现象,进行了税法教学改革尝试。通过对教学改革实践的分析与总结,归纳税法教学改革元素,建立基于项目导向、任务驱动的税法教学改革模型。我们基于办税员岗位,注重实践操作,并对其在教学实践中的运用效果进行评价。通过教学改革,激发学生学习税法的兴趣,应学生所求,教学生所需,利用多种资源,为学生创造良好的税法学习条件和环境,实现教与学的良性互动。     

弯曲河道对水流流态影响数值模拟

蜿蜒型河流是冲积平原常见的河型之一。针对具体河流的特定自然条件,需要对不同河道形态下的河道特性做出预测,以便选择和调整相应方案。采用集水动力模块、泥沙输运模块、污染物运移模块和水质预测模块为一体的环境流体动力学模型,利用计算机进行数值模拟,对京郊某弯曲河道3种河道形态在50年一遇洪水过程下进行数值模拟,在此基础上对3种工况下河道的水流特性进行分析,发现工况一弯道处凸岸流速先增加后减小,凹岸流速先减小后增大,凹岸水位明显高于凸岸水位;工况二两岸流速分布较为对称,叉道起到分洪滞洪作用;工况三两岸水流摆动现象不如工况一明显,衬砌工程量较小,并提出相应河道保护措施。     

A numerical study of tournament structure and seeding policy for the soccer World Cup Finals

Tournament outcome uncertainty depends on: the design of the tournament; and the relative strengths of the competitors – the competitive balance. A tournament design comprises the arrangement of the individual matches, which we call the tournament structure, the seeding policy and the progression rules. In this paper, we investigate the effect of seeding policy for various tournament structures, while taking account of competitive balance. Our methodology uses tournament outcome uncertainty to consider the effect of seeding policy and other design changes. The tournament outcome uncertainty is measured using the tournament outcome characteristic which is the probability P_q,R that a team in the top 100q pre‐tournament rank percentile progresses forward from round R, for all q and R. We use Monte Carlo simulation to calculate the values of this metric. We find that, in general, seeding favours stronger competitors, but that the degree of favouritism varies with the type of seeding. Reseeding after each round favours the strong to the greatest extent. The ideas in the paper are illustrated using the soccer World Cup Finals tournament.     

螺旋机构运动精度可靠性设计

将螺旋机构的诸原始误差视为随机变量,对螺旋机构具有螺距累积误差、中径锥度和椭圆度误差、牙型半角误差等各项随机变量分别进行了分析;运用微小位移的线性迭加原理,综合出各项误差导致的机构运动输出总误差,建立了机构运动精度可靠性分析模型;利用计算机数字仿真技术,考察了机构各项误差导致的机构运动输出总误差对机构输出运动精度可靠性的影响,从中获得了一些有意义的结论。