弹丸跨声速粘性绕流数值计算

用数值模拟方法研究弹丸跨声速绕流的流动特性,数值模拟的出发方程为平均雷诺数的Ｎ－Ｓ方程,湍流模型有用Ｂａｌｄｗｉｎ－Ｌｏｍａｘ模型,数值格式为四阶的ＭＵＳＣＬ ＴＶＤ格式。     

带端板地效应翼性能的数值研究

通过求解不可压缩流体ＲＡＮＳ方程,数值模拟带端板三维地效应翼的性能及周围流场。数值方法引进了Ｃｈｏｒｉｎ的人工可压缩性概念,应用近似因式分解技术同时求解速度和压力场,动量方程对流项用二阶迎风差分格式离散,其余空间导数项均采用四阶精度的中心差分格式离散,时间离散采用欧拉隐式格式,计算在非交错网格上进行,为了避免压力场的振荡,在连续方程中隐式地加入了压力的四阶数值耗散项,湍流计算采用了Ｂａｌｄｗｉｎ－     

燃气射流CFD计算软件初版本的研究

目的 发展一个燃气射流数值计算软件。方法 用时间相关法求解全ＮＳ方程及Ｒｅｙｎｏｌｄｓ平均应力方程,方程的时间项采用了ＬＵ分解及４步Ｒｕｎｇｅ－Ｋｕｔｔａ方法,对流项采用了Ｒｏｅ差分分裂基础上的３阶ＴＶＤ级２阶、３阶ＥＮＯ格式。结果与结论软件可应用于轴对称,三维燃气射流计算,格式具有高分辩和健壮稳定性,能够捕获复杂波系,计算出射流中波系与剪切层的相互作用和湍流特征。     

用改进的强隐式方法求解三维不可压粘性流动问题

提出了一种用改进的强隐式方法求解三维不可压缩粘性流动的交错网格有限体积法．该方法在ＳＩＭＰＥＲ算法的基础上，对Ｎ－Ｓ方程的对流项采用ＱＵＩＣＫ格式离散，利用ＭＳＩ方法求解代数方程．数值计算表明本方法具有计算稳定、收敛速度快等特点．     

旋风分离器气相流场的数值模拟

为了考察适合旋风分离器流场模拟的湍流模型,采用三维贴体网格,应用ＰＨＯＥＮＩＣＳ程序对某旋风分离器气相流场进行了数值模拟,湍流模型分别采用标准ｋ－ε模型和Ｃｈｅｎ－Ｋｉｍ模型。通过计算结果与实验数据的对比发现,与标准ｋ－ε模型相比较,Ｃｈｅｎ－Ｋｉｍ模型更适合于模拟涡旋流动,可以用来进行旋风分离器流场模拟。     

基于微元指数拟合的湍流控制方程离散格式初探

针对Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程及各种湍流模型之控制方程的数值解，提出了微元指数拟合的概念，并以ｋ－ε模型为例建立起了一个新的离散格式。     

180°方形弯管中湍流流动的大涡模拟

把大涡模拟应用于复杂几何形状的流域是一个重要研究课题。对１８０°方形弯管中的湍流流动作大涡模拟,以网格节点为中心的交错网格作为离散网格,用有限体积方法和中心差分进行空间离散,用Ａｄａｍｓ－Ｂａｓｈｆｏｒｔｈ格式进行时间离散,用简单的Ｓｍａｇｏｒｉｎｓｋｙ模型来作为次网格湍流模型。用多重网格方法求解压力方程以提高计算效率。数值模拟结果与实验结果取得了很好的一致。     

K-∈湍流模型下门桥水阻力的数值计算

采用RANS方程和RNGκ-ε二方程湍流模型及VOF算法对绕门桥的自由表面流动进行了数值计算。数值计算时，使用有限体积法离散控制方程，对流项采用二阶迎风差分格式，扩散项采用中心差分格式。对门桥模型进行了一系列速度下的数值模拟；计算结果与试验测量数据相比较，该计算方法具有较好的计算精度，可用于门桥性能分析和优化。     

DARPA2潜艇模型定常绕流水动力数值计算

自主开发了数值求解RANS方程的CFD计算软件.采用多块结构化网格的有限体积法,各块间网格线在交界面处正接,并有一层网格的重叠,便于块间的信息交换;采用SIMPLE方法和动量插值法处理速度-压力耦合;对流项的离散有多种差分格式选项,如一阶迎风(FOU)、二阶迎风(SOU)、中心差分(CD)、QUICK和NND等格式,扩散项采用中心差分格式离散;可选择的湍流模式有高雷诺数k-ε模型加壁函数,SA和SST三种湍流模式;给出了DARPA2潜艇模型大攻角定常流场和水动力的数值计算结果,并与国外文献的实验结果进行了比较,两者符合很好.     

高阶差分格式的离散方法及其应用研究

在提出亚边界的同时，通过对包含亚边界在内的边界控制网格的细化处理，发展了以一阶迎风为基的高阶差分格式离散方法，并将该方法推广应用于三阶QUICK格式和AHARP格式对液钠方腔内的热分层流动的数值模拟中，解决了应用湍流标准。κ－ε模型模拟热分层流动过程中高阶差分格式隐式数值计算的收敛问题。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

正~~     

An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.