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71.
72.
Compared to other fields of engineering, in mechanical engineering, the Discrete Element Method (DEM) is not yet a well known
method. Nevertheless, there is a variety of simulation problems where the method has obvious advantages due to its meshless
nature. For problems where several free bodies can collide and break after having been largely deformed, the DEM is the method
of choice. Neighborhood search and collision detection between bodies as well as the separation of large solids into smaller
particles are naturally incorporated in the method. The main DEM algorithm consists of a relatively simple loop that basically
contains the three substeps contact detection, force computation and integration. However, there exists a large variety of
different algorithms to choose the substeps to compose the optimal method for a given problem. In this contribution, we describe
the dynamics of particle systems together with appropriate numerical integration schemes and give an overview over different
types of particle interactions that can be composed to adapt the method to fit to a given simulation problem. Surface triangulations
are used to model complicated, non-convex bodies in contact with particle systems. The capabilities of the method are finally
demonstrated by means of application examples.
Commemorative Contribution. 相似文献
73.
朝阳沟裂缝性低渗透油田井网适应性研究 总被引:23,自引:13,他引:10
通过对比分析朝阳沟裂缝性低渗透油藏与裂缝主方向分别成11.5°和22.5°的两种不同井网的开发效果,表明与裂缝成11.5°的井网与裂缝匹配性较差,开发效果相对较差。并从油藏的水驱控制程度、压力传导情况、采收率及经济效益等方面研究评价了朝1.55区井网的适应性,为指导油田的加密调整,在技术和经济两方面综合评价确定了合理的井距和井网密度,并针对朝1-55区的地质特征,提出了井网和注水方式调整办法,在朝55区块实施后,取得了较好的现场试验效果。 相似文献
74.
75.
对裂隙岩体中掏糟爆破布孔的影响因素进行了研究,并根据裂分布的情况提出相应的布孔方法和原则。对有关的工程施工具有实际意义。 相似文献
76.
防腐涂料及涂装技术讲座系列介绍防腐蚀涂料的品种和各类应用及最新产品研究进展。本讲主要介绍涂装前的表面预处理方法及表面处理质量的评定等 相似文献
77.
78.
During the day, there are considerable variations in the climatic factors prevailing in these regions. This is especially so during the 24-hour daily cycle of the long, hot and dry summer (mid-May to midOctober). Such climatic conditions have had a considerable impact on the daily living pattern of family life in the same season, particularly in the urban areas. During the same 24-hour cycle, they have compelled the inhabitants to shift their living activities both vertically in section and horizontally in plan; they do this in pursuit of more acceptable, if not, desirable internal thermal environmental ambience. 相似文献
79.
80.
In order to cumpare the peformance of different supply diffuers of ventilation air, the airflow passern, temperature stratifiation and contaminant dispersion in a furnitured office ventilated by three kinds of air diffuer were numerically investigated. The air diffuers studied in this paper are a quarter-cylinder displacement diffuer on the floor and mixing diffuers (linear and vortex diffuers) on the ceiling. The heat sources in the of-fice are considered to be 50% convective and 50% radiative. The k-? two-equatwn model of turbulence is employed to predict the turbulent diffusion. The results show that the displacement diffuser provides a rather uniform flow field with low velocify in most areas, and the vertical temperature difference from floor to ceiling is as high as 6 K. With the linear diffuser, the air velociry is high, and the temperature is uniform both horizontally and vertically. The air velocity generated by the vortex diffuser is moderate. The distributions of the temperature and the contaminant are rather uniform. 相似文献