The unsymmetrical bending of cantilever rectangular plates

This paper discusses the problems of the unsymmetrical bending of cantilever rectangular plates under various loads by the energy method. We illustrate numerous calculating examples such as the plates which are subjected by the concentrated forces or concentrated couples unsymmetrically on free sides and corner points and by a uniformly or nonuniformly distributed loads unsymmetrically on free edges and so forth.     

Simulation and application of three-dimensional migration-accumulation of oil resources

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｏｉｌｆｏｒｍａｔｉｏｎｉｎｓｅｄｉｍｅｎｔｂａｓｉｎｓ,ｉｔｓｄｉｓｐｌａｃｅｍｅｎｔ,ｔｒａｎｓｐｏｒｔａｎｄａｃｃｕｍｕｌａｔｉｏｎ,ａｎｄｔｈｅｆｉｎａｌｆｏｒｍａｔｉｏｎｏｆｏｉｌｄｅｐｏｓｉｔｓｈａｖｅｂｅｅｎｔｈｅｋｅｙｐｒｏｂｌｅｍｓｉｎｔｈｅｅｘｐｌｏｒａｔｉｏｎｏｆｏｉｌ＿ｇａｓｒｅｓｏｕｒｃｅｓ．Ｈｏｗｈａｓｏｉｌｂｅｅｎａｃｃｕｍｕｌａｔｅｄｉｎｔｈｅｐｒｅｓｅｎｔｌｏｏｐａｃｃｏｒｄｉｎｇｔｏｔｈｅｍｅｃｈａｎｉｃｓｏｆｉｍｍｉｓｃｉｂｌｅ…     

Careful numerical simulation and analysis of migration-accumulation of Tanhai Region

Numerical simulation of careful parallel arithmetic of oil resources migration-accumulation of Tanhai Region (three-layer) was done. Careful parallel operator splitting-up implicit iterative scheme, parallel arithmetic program, parallel arithmetic information and alternating-direction mesh subdivision were put forward.Parallel arithmetic and analysis of different CPU combinations were done. This numerical simulation test and the actual conditions are basically coincident. The convergence estimation of the model problem has successfully solved the difficult problem in the fields of permeation fluid mechanics, computational mathematics and petroleum geology.     

NUMERICAL SIMULATION OF OIL MIGRATION-ACCUMULATION OF MULTILAYER AND ITS APPLICATION

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｏｉｌｆｏｒｍａｔｉｏｎｉｎｓｅｄｉｍｅｎｔｂａｓｉｎｓ ,ｉｔｓｄｉｓｐｌａｃｅｍｅｎｔ,ｔｒａｎｓｐｏｒｔａｎｄａｃｃｕｍｕｌａｔｉｏｎ ,ａｎｄｔｈｅｆｉｎａｌｆｏｒｍａｔｉｏｎｏｆｏｉｌｄｅｐｏｓｉｔｓｈａｖｅｂｅｅｎｏｎｅｏｆｔｈｅｋｅｙｐｒｏｂｌｅｍｓｉｎｔｈｅｅｘｐｌｏｒａｔｉｏｎｏｆｏｉｌ＿ｇａｓｒｅｓｏｕｒｃｅｓ.Ｈｏｗｈａｓｏｉｌｂｅｅｎａｃｃｕｍｕｌａｔｅｄｉｎｔｈｅｐｒｅｓｅｎｔｌｏｏｐａｃｃｏｒｄｉｎｇｔｏｔｈｅｍｅｃｈａｎｉｃｓｏｆｉｍｍｉｓｃ…     

Numerical simulation analysis for migration-accumulation of oil and water

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｔｈｅｅｖｏｌｕｔｉｏｎａｒｙｈｉｓｔｏｒｙｏｆｔｈｅｂａｓｉｎｉｓｃｏｎｄｕｃｔｅｄａｃｏｒｄｉｎｇｔｏｔｈｅｍｅｃｈａｎｉｓｍｏｆｐｅｔｒｏｌｅｕｍｇｅｏｌｏｇｙａｎｄｍｅｃ...     

Krylov subspace projection method and its application on oil reservoir simulation

ＩｎｔｒｏｄｕｃｔｉｏｎＭａｎｙｐｒｏｂｌｅｍｓｏｆｅｎｇｉｎｅｅｒｉｎｇｉｎｔｅｒｅｓｔ,ｉｎｃｌｕｄｉｎｇｐｒｏｂｌｅｍｓｏｆｏｉｌｒｅｓｅｒｖｏｉｒｓｉｍｕｌａｔｉｏｎ,ｌｅａｄｔｏｔｈｅｔａｓｋｏｆｓｏｌｖｉｎｇａｓｙｓｔｅｍｏｆｌｉｎｅａｒｅｑｕａｔｉｏｎｓＡｘ=ｆ,(1)ｗｈｅｒｅＡｉｓａｎｎ×ｎ,ｒｅａｌ,ｌａｒｇｅｓｐａｒｓｅ,ｎｏｎ＿ＳＰＤｍａｔｒｉｘ.Ｔｈｅｄｉｒｅｃｔｄｅｃｏｍｐｏｓｉｔｉｏｎｍｅｔｈｏｄｉｓｍｏｓｔｅｆｆｉｃｉｅｎｔｓｏｌｖｅｒｗｈｅｎｎｉｓｓｍａｌｌ.Ｈｏｗｅｖｅｒ…     

泥水平衡盾构机掘进并行数值模拟方法研究

以某大型越江隧道工程为背景,建立该工程场地土层的大规模三维非线性数值模型。同时基于共享内存式并行计算平台(SMP),利用刚度迁移法,完成了泥水平衡盾构机逐步掘进百米长距离,并穿越大堤这一复杂力学过程的大规模数值模拟。为模拟泥水平衡盾构机掘进各施工阶段,不同施工因素之间的复杂力学作用关系,提出了对各施工因素模拟的简化方法。具体包括:开挖面泥水压力对前方土体的作用、盾构机机头的超挖、盾构机机身对土体的作用、盾尾注浆材料的时空变化特性、盾构机后方百米长拖车对已铺成隧道的作用等施工因素。通过对计算结果与工程试验段实测数据对比验证的基础上,预测了地表沉降在盾构机掘进过程中的变化规律。通过对SMP并行计算平台下盾构法施工数值模型之并行计算效率的对比研究,给出了各并行算法的加速比、计算效率以及接触模型对并行计算效率的影响关系。     

建筑风压数值模拟的几种并行化策略

针对四个处理机的Ｔｒａｎｓｐｕｔｅｒ并行计算机系统，建立了建筑风压数值模拟问题基于ＳＩＭ－ＰＬＥＣ算法的几种并行化策略：分区并行策略、方程并行策略和双重并行策略。对各种策略的计算流程、数据通讯及并行效率等进行了分析和比较，并通过实例计算作了验证。     

聚能装药的欧拉数值模拟

用二维有限差分欧拉程序MEPH2Y模拟了聚能装药的作用过程,包括爆轰波的形成、传播及与其他介质的相互作用,高温高压下射流（或射弹）的形成、延展、减压、断裂,射流（或射弹）对靶的侵彻及靶的成坑和动态响应等过程。介绍了程序所用的数学模型、数值方法,以及模拟的部分问题与实验结果的比较。结果表明,数值模拟结果与实验结果符合较好。     

动态存储方法在气相爆轰波数值模拟中的应用

为减少反应流计算花费的时间,采用动态存储建立热力学数据表（In situ adaptive tabulation, ISAT）的方法来取代反应流计算中化学反应的直接积分（Direct integral, DI）,并针对气相H2/O2爆轰波的传播过程进行了数值模拟。采用两种不同的ISAT误差放大判据对一维爆轰波的压力、温度及组分变化进行了计算,并和DI的结果进行了比较以考察其计算精度。此外,还探讨了ISAT方法的效率。计算结果表明,和DI方法相比,在爆轰波传播计算中ISAT方法计算误差小于3％,化学反应计算速度提高了8倍。     

Theory and application of numerical simulation method of capillary force enhanced oil production

A kind of second-order implicit upwind fractional step finite difference methods are presented for the numerical simulation of coupled systems for enhanced(chemical)oil production with capillary force in the porous media.Some techniques,e.g.,the calculus of variations,the energy analysis method,the commutativity of the products of difference operators,the decomposition of high-order difference operators,and the theory of a priori estimate,are introduced.An optimal order error estimate in the l~2 norm is derived.The method is successfully used in the numerical simulation of the enhanced oil production in actual oilfields.The simulation results are satisfactory and interesting.     

岩石双孔爆破过程的流形元法模拟

在流形元基本理论基础上,引入断裂力学的裂纹产生及扩展判据,应用二阶流形元对岩石双孔爆破过程进行了研究,模拟了双孔同时起爆和毫秒延时起爆两种条件下裂纹的产生和扩展、块体的形成以及漏斗形成过程,分析了爆炸载荷作用下岩石的破坏规律以及起爆条件对该过程的影响,验证了流形元法在研究冲击载荷作用下岩石从连续体到不连续体破坏过程的准确性和有效性,为研究类似问题提供一个新的思路和方法。     

A coupled model for multiphase fluid flow and sedimentation deformation in oil reservoir and its numerical simulation

A mathematical model for coupled multiphase fluid flow and sedimentation deformation is developed based on fluid-solid interaction mechanism. A finite difference-finite element numerical approach is presented. The results of an example show that the fluid-solid coupled effect has great influence on multiphase fluid flow and reservoir recovery performances, and the coupled model has practical significance for oilfield development.     

混凝土中爆炸数值仿真算法研究

用AUTODYN动力学软件对装药在混凝土介质靶中爆炸作数值仿真,研究了不同的网格描述方法,以及网格划分方法对计算结果的影响。通过实际算例比较了Lagrange算法和SPH算法以及不同的网格划分细度对靶径向、轴向不同距离的最大冲击压力、靶背过载以及损伤区、炸坑大小的模拟计算结果。分析得到了混凝土介质靶中爆炸问题数值仿真的合适算法,即拉氏算法对炸点近处的较高的最大冲击压力有较好的敏感能力,SPH算法对仿真计算爆坑形态以及抛掷体速度等具有明显的优势。对于算例问题,拉氏算法10 mm网格和SPH算法3 mm粒子即可满足一定的计算精度。     

弹塑性变形油藏中多相渗流的数值模拟

基于流固耦合力学理论,建立了弹性变形油藏中多相渗流的数学模型,该模型考虑了渗流与变形的耦合作用,以及注采交变载荷作下油藏多孔介质的弹性变形特征,给出了耦合数值模拟方法和算例。     

Study of numerical errors in direct numerical simulation and large eddy simulation

By comparing the energy spectrum and total kinetic energy, the effects of numerical errors (which arise from aliasing and discretization errors), subgrid-scale (SGS) models, and their interactions on direct numerical simulation (DNS) and large eddy simulation (LES) are investigated. The decaying isotropic turbulence is chosen as the test case. To simulate complex geometries, both the spectral method and Pade compact difference schemes are studied. The truncated Navier-Stokes (TNS) equation model with Pade discrete filter is adopted as the SGS model. It is found that the discretization error plays a key role in DNS. Low order difference schemes may be unsuitable. However, for LES, it is found that the SGS model can represent the effect of small scales to large scales and dump the numerical errors. Therefore, reasonable results can also be obtained with a low order discretization scheme.     

水下爆炸冲击波的数值模拟研究

应用商业有限元程序MSC.DYTRAN数值模拟了球形药包在无限水域中爆炸产生的冲击波。通过和经验公式计算结果的比较,证明采用合理的计算参数和有限元模型能够较好地模拟水下爆炸冲击波的传播过程。通过调整水的状态方程参数,达到了提升冲击波峰值应力的效果,从而有效地降低了单元数量和计算时间。     

A model for simulation of friction phenomenon between dies and workpiece

Based on the interaction of asperities and upperbound approach a mathematical model for simulation of friction phenomenon between dies and workpiece is proposed. Optimizing the mathematical model with respect to several variables it is found that in addition to adhering, tearing, ploughing, etc., asperities workpiece can move wave-like along the surface layer and under certain circumstances they may disappear. If the asperities wavily move along the surface layer the friction coefficient depends on the geometry of asperities. However, the bonding strength of asperities has no significant influence on friction coefficient. The depth of the plastic deformation layer is related to the geometry of asperities, too. The soundness of the prerequisite of the proposed model and some analytical results were verified by experiments.Department of Materials Engineering, Northwestern Polytechnical UniversityThis is a project of the cooperative program between the Department of Materials Engineering of Northwestern Polytechnical University of the People's Republic of China and the Institute for Metal Forming at Lehigh University of the United States of America.     

Characteristic finite difference method and application for moving boundary value problem of coupled system

The coupled system of multilayer dynamics of fluids in porous media is to describe the history of oil-gas transport and accumulation in basin evolution.It is of great value in rational evaluation of prospecting and exploiting oil-gas resources.The mathematical model can be described as a coupled system of nonlinear partial differential equations with moving boundary values.A kind of characteristic finite difference schemes is put forward,from which optimal order estimates in l^2 norm are derived for the error in the approximate solutions.The research is important both theoretically and practically for the model analysis in the field,the model numerical method and software development.     

基于误差马尾图量化爆轰数值模拟结果的置信度

针对爆轰流体力学数值模拟过程中输入参数的不确定性, 通过抽样技术, 形成确定性爆轰流体力学程序的各种输入和数值求解, 建立输入参数与输出响应量的样本, 再通过概率框架下的误差累积分布函数与马尾图, 给出了爆轰数值模拟过程中输入参数不确定度对模拟结果影响的置信度量化方法。通过一维黎曼问题、平面爆轰问题计算了误差马尾图, 给出了二维爆轰拉氏自适应流体动力学LAD2D程序计算网格与模拟结果置信度的关系, 对多物理爆轰过程发展高置信度数值模拟软件有很好的借鉴作用。