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1.
通过基本解的多极展开与边界元线性方程组的隐式求解方法(GMRES)相结合,开发出了快速多极边界元法。Taylor级数多极边界元法更新了传统边界元法的求解模式,大大提高了计算效率,扩大了边界元法的求解规模。介绍了Taylor级数多极边界元法的发展历史和现状,给出了Taylor级数多极边界元法的基本思想、基本原理和分类,给出了基本解的Taylor展开方法和边界积分的基本实现步骤。将该方法应用于轧制工程中,通过轧辊弹性变形和HC轧机辊系接触和变形的数值解析,说明了Taylor级数多极边界元法适合于大规模轧制工程  相似文献   

2.
采用四阶(三次)样条小波尺度函数,构造了函数的B样条小波插值格式,并将其应用于梁的弯曲问题边界元法.算例的计算结果与精确解完全一致.文中给出的样条小波插值函数,可应用于其他有限元法、边界元法的的计算.  相似文献   

3.
通过将全空间内轴对称异质体边界载荷沿周向作Fourier级数展开,然后利用边界元法在母线方向求解边界积分方程,使弹性波散射问题的维数由三维降到一维.该方法充分利用旋转体轴对称的几何特点,采用环壳单元使计算量较普通边界元法更小,并且收敛速度较其他边界元法更快.  相似文献   

4.
通过将全空间内轴对称异质体边界载荷沿周向作Fourier级数展开,然后利用边界元法在母线方向求解边界积分方程,使弹性波散射问题的维数由三维降到一维。该方法充分利用旋转体轴对称的几何特点,采用环壳单元使计算量较普通边界元法更小,并且收敛速度较其他边界元法更快。  相似文献   

5.
研究了平面叶栅在线性化小扰动范围的亚音速可压缩位势流场的三种边界元法计算途径。其一是移用正交异性域位势问题的边界元法;其二是先把物理平面内的亚音速可压缩流场变换成计算平面内的不可压缩流场,再用边界元法进行计算;方法之三是用压缩性修正法对不可压缩流场的边界元法计算结果进行修正。算例表明了这三种处理方法各自的特点。  相似文献   

6.
用边界元法分析横电磁波传输室的特性阻抗   总被引:1,自引:0,他引:1  
本文提出用边界元法计算横电磁波传输室的重要参数-特性阻抗。为检验边界元法的计算精度,边界元法分别计算了有效析解的零厚横电磁波传输室和无解析解的几种常用横电磁波传输室。  相似文献   

7.
快速多极方法能够有效地提高边界元法的计算效率.求解的计算量和内存量与问题的自由度数N成正比.求解的精度与传统边界元法相比有所下降.分析了Taylor级数多极边界元法的计算精度和远场影响系数的误差.研究了核函数r的Taylor级数展开性质,推导了三维弹性问题基本解的误差估计公式.说明了影响多极边界元法计算精度的因素.数值算例显示了误差估计公式的正确性和有效性.  相似文献   

8.
基于NURBS边界元法的波浪荷载计算研究   总被引:1,自引:1,他引:0  
应用基于NURBS的边界元法对船舶在波浪中的运动和荷载计算进行了研究.基于NURBS边界元法原理编制了相应的边界元法计算程序.对构建线性方程组的配点法和Galerkin法进行了比较,验证了两种方法的计算精度,结果表明Galerkin法计算结果的精度要好于配点法.使用基于NURBS的边界元法和频域三维移动脉动源格林函数,对一艘集装箱船在波浪中的运动和受到的波浪弯矩进行了计算,计算结果同已有的实验结果和数值计算结果符合良好.  相似文献   

9.
本文应用边界元法计算电磁机构中的气隙磁导。文中阐明了应用边界元法计算气隙磁导的基本原理。通过电子计算机计算的两个典型例子,便可看出,它与其他的数值法,如差分法,有限元法相比,不但具有计算方法较简单,而且精确度高等的优点。是一种目前用来计算具有二维场或近似二维场性质的气隙磁导较好的数值法。  相似文献   

10.
该文将快速多极子算法和处理强奇异积分的正则化算法应用于传统边界元法中,开发了正则化快速多极子边界元法。该方法既可以解决传统边界元法计算量和存储量会随着单元数量的增加而快速增加的问题,也可以处理边界元法求解势流速度和速度梯度时产生的强奇异性积分问题。将所开发的方法应用于绕球势流的数值计算中,计算结果证明了方法的可靠性和高效性;对相关计算参数影响的分析为复杂边界流动问题的计算提供了参考依据。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
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.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
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。  相似文献   

18.
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.  相似文献   

19.
20.
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  相似文献   

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