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1.
Effects of the geometry of two‐dimensional fractures on their hydraulic aperture and on the validity of the local cubic law 下载免费PDF全文
Flow through rough fractures is investigated numerically in order to assess the validity of the local cubic law for different fracture geometries. Two‐dimensional channels with sinusoidal walls having different geometrical properties defined by the aperture, the amplitude, and the wavelength of the walls' corrugations, the corrugations asymmetry, and the phase shift between the two walls are considered to represent different fracture geometries. First, it is analytically shown that the hydraulic aperture clearly deviates from the mean aperture when the walls' roughness, the phase shift, and/or the asymmetry between the fracture walls are relatively high. The continuity and the Navier–Stokes equations are then solved by means of the finite element method and the numerical solutions compared to the theoretical predictions of the local cubic law. Reynolds numbers ranging from 0.066 to 66.66 are investigated so as to focus more particularly on the effect of flow inertial effects on the validity of the local cubic law. For low Reynolds number, typically less than 15, the local cubic law properly describes the fracture flow, especially when the fracture walls have small corrugation amplitudes. For Reynolds numbers higher than 15, the local cubic law is valid under the conditions that the fracture presents a low aspect ratio, small corrugation amplitudes, and a moderate phase lag between its walls. 相似文献
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The FAST/SKA site selection in Guizhou province 总被引:1,自引:0,他引:1
Many karst depressions with diameters of 300 m to 500 m, suitable for constructing Arecibo-style radio telescopes, were identified
in the south of Guizhou Province by Remote Sensing (RS) and Geographic Information System (GIS) technologies together with
field investigations. Fundamental topography and landform databases were established for 391candidate depressions, and using
GIS the3-dimensional images of depressions, at a scale of 1:10000, were then simulated to fit a spherical antenna.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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应用勘探层分析及石油资源专家系统对XH凹陷下第三系勘探目的层的三个勘探层烃资源量作出了综合预测,结果表明,凹陷内各勘探层,尤其是渐新统勘探层,烃资源量相当可观。提出在渐新统内的地层圈闭中可进一步作详细的勘探工作。 相似文献
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F. D. Por 《Marine Ecology》1980,1(2):121-131
Abstract. A classification of hypersaline waters is proposed on the basis of the food chain structure of their biota. Four steps of increasing salinity and respective shortening of the food-chains are recognized, respectively named: alpha-, beta-, gamma- and delta-hypersaline waters.
Some general aspects, dealing with cosmopolitism of the biota, production, competition and benthic ecology in hypersaline waters are discussed.
The relevance of ecological studies in hypersaline waters to theoretical ecology and to the new technological uses of saline waters is briefly mentioned. 相似文献
Some general aspects, dealing with cosmopolitism of the biota, production, competition and benthic ecology in hypersaline waters are discussed.
The relevance of ecological studies in hypersaline waters to theoretical ecology and to the new technological uses of saline waters is briefly mentioned. 相似文献
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Based on the Nansha Islands' closed atoll conception-remote sensing system in Part Ⅰ,through the solution of the information function value and isostatic value of closed and quasi-closed atoll, and by using topological analysis on growth form and the composite remote sensing quantization date as the calculating coefficients, the feature vector system and its mathematical model of two kinds of atoll are built, and the multivariate analysis is made with some examples. 相似文献
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