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111.
D. LE GOURIÉRÈS 《水文科学杂志》2013,58(3):301-313
ABSTRACT In this paper, the author relies on Darcy's law and on an hypothesis formulated from experimental considerations to establish a semi-empirical formula for the calculation of the discharge of partially penetrating wells of free aquifer sunk in isotropic soils. This relatively simple relation applied to 27 cases studied under an experimental design or numerical computations, reveals itself to have an unexpected accuracy. Starting from previous formula, the author establishes another one for partially penetrating wells bored in anisotropic soils. 相似文献
112.
ANDRÉ RENAUD 《水文科学杂志》2013,58(2):109-116
Abstract The authors give data of water infiltrations in horizontal and vertical columns, and in a two dimensional model. The soils are two mixtures of sand and loam, and a natural sandy loam. The characteristics of these soils are given in the article. As a conclusion, the two dimensional problem can be approached by a linear combination of data in horizontal and vertical columns. 相似文献
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114.
Vertical ground motion (VGM) rates stand as crucial information, either for predicting the impact of the actual sea level rise along low-lying coasts or refining geodynamic problems. Because present day VGM rates have a magnitude smaller than 10 mm/yr, they remain challenging to quantify and often elusive. We focus on the quantification of global-scale VGM rates in order to identify global or regional trends. We computed VGM rates by combining tide gauges records and local satellite altimetry, which yield a new dataset of 634 VGM rates. We further compare this database to previous studies that use geodetic techniques and tide gauges records in order to evaluate the consistency of both our results and previous ones. The magnitudes differ by less than 5 mm/yr, and similar subsidence and uplift general tendencies appear. Even if the asset of our database stands in the greater number of sites, the combination of all studies, each with different pros and cons, yields a hybrid dataset that makes our attempt to extract VGM trends more robust than any other, independent study. Fennoscandia, the West coast of North America, and the eastern coast of Australia are uplifting, while the eastern coast of North America, the British Isles and Western Europe, the eastern Mediterranean Sea, Japan, and the western coast of Australia are subsiding. Glacial Isostatic Adjustment (GIA) is expected to provide a major contribution to the present-day signal. Aside from Fennoscandia, observed VGM often depart from the GIA model predictions of Peltier (2004). This either results from an underestimate of the model predictions or from the influence of other processes: indeed, the influence of the geodynamic setting appears in particular along the coasts of western North America or Japan, where the alternation of transform faults and subduction zones makes it possible to assign contrasted behaviours to the local geodynamic context. Local mechanisms like anthropogenic processes or sediment compaction, also contribute to VGM. This remains true for the critical cases of Venice, the Gulf of Mexico, the Ganges delta, and the Maldives, which are particularly exposed to the current sea level rise. 相似文献
115.
Bruno Bueno Leslie Norford Grégoire Pigeon Rex Britter 《Boundary-Layer Meteorology》2011,140(3):471-489
A scheme that couples a detailed building energy model, EnergyPlus, and an urban canopy model, the Town Energy Balance (TEB), is presented. Both models are well accepted and evaluated within their individual scientific communities. The coupled scheme proposes a more realistic representation of buildings and heating, ventilation and air-conditioning (HVAC) systems, which allows a broader analysis of the two-way interactions between the energy performance of buildings and the urban climate around the buildings. The scheme can be used to evaluate the building energy models that are being developed within the urban climate community. In this study, the coupled scheme is evaluated using measurements conducted over the dense urban centre of Toulouse, France. The comparison includes electricity and natural gas energy consumption of buildings, building façade temperatures, and urban canyon air temperatures. The coupled scheme is then used to analyze the effect of different building and HVAC system configurations on building energy consumption, waste heat released from HVAC systems, and outdoor air temperatures for the case study of Toulouse. Three different energy efficiency strategies are analyzed: shading devices, economizers, and heat recovery. 相似文献
116.
A new Mazon-Creek-type fossil specimen is described as Sumixam maximus gen. and sp. nov., assigned to the taxon Archaeorthoptera Béthoux and Nel, 2002 (composed of Orthoptera and some fossil relatives): it exhibits one of the diagnostic character states of this taxon, which is the fusion of CuA (emerging from M + CuA) with CuP, or a branch of it. A more precise taxonomic assignment is out of reach. The new taxon exhibits a fusion of the anterior branch of MA with RP, and a point of divergence of MA and MP located near the point of divergence of CuA (from M + CuA), but lack a branching of CuPa. This unique combination of character states is probably derived with respect to a number of contemporaneous species. Sumixam maximus gen. and sp. nov. is most likely the closest known relative of the panorthopterans, which include all the recent Archaeorthoptera. 相似文献
117.
Ulf Gräwe 《Ocean Modelling》2011,36(1-2):80-89
Stochastic differential equations (SDEs) offer an attractively simple solution to complex transport-controlled problems, and have a wide range of physical, chemical, and biological applications, which are dominated by stochastic processes, such as diffusion. As for deterministic ordinary differential equations (ODEs), various numerical scheme exist for solving SDEs. In this paper various particle-tracking schemes are presented and tested for accuracy and efficiency (time vs. accuracy). To test the schemes, the particle tracking algorithms are implemented into a community wide used 1D water column model. Modelling individual particles allows a straightforward physical interpretation of the involved processes. Further, this approach is strictly mass conserving and does not suffer from the numerical diffusion that plagues grid-based methods. Moreover, the Lagrangian framework allows to assign properties to the individual particles, that can vary spatially and temporally. The movement of the particles is described by a stochastic differential equation, which is consistent with the advection–diffusion equation. Here, the concentration profile is represented by a set of independent moving particles, which are advected according to the velocity field, while the diffusive displacements of the particles are sampled from a random distribution, which is related to the eddy diffusivity field.The paper will show that especially the 2nd order schemes are accurate and highly efficient. At the same level of accuracy, the 2nd order scheme can be significantly faster than the 1st order counterpart. This gain in efficiency can be spent on a higher resolution for more accurate solutions at a lower cost. 相似文献
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119.
The rocky coastline of the Sultanate of Oman between Fins and Sur is decorated by a number of large blocks and boulder accumulations forming ramparts. The blocks occur as individual rocks of up to 40 tons, as imbricated sets and as ??boulder trains.?? Landward, the deposits change into a sand/boulder mixture and distal into sands. The coast is made up of Tertiary folded limestones and beach rock of Quaternary age, both also constitute the megaclasts. The transport distance from the fractured seaward platform of 6?C10?m above mean sea level varies between 20?m and more than 50?m. We found individual blocks of recent corals and overturned blocks with attached oysters and rock pools. Terrestrial laser scanning was used to analyze geomorphologic features as well as for volumetric estimates of the block weights. Tropical cyclones such as Gonu in 2007 or Phet in 2010 are known to have affected Oman??s coastline in the past. The coastal changes during recent cyclones were minor; therefore, we interpret the block deposits as tsunamigenic. However, this interpretation is not unambiguous. The most likely source area for a tsunami is seen in the Makran Subduction Zone situated in the northern Indian Ocean. Here, at least 4?C5 tsunamigenic earthquakes are documented. 相似文献
120.
Grégoire Allaire Robert Brizzi Jean-François Dufrêche Andro Mikelić Andrey Piatnitski 《Computational Geosciences》2013,17(3):479-495
In this work, we undertake a numerical study of the effective coefficients arising in the upscaling of a system of partial differential equations describing transport of a dilute N-component electrolyte in a Newtonian solvent through a rigid porous medium. The motion is governed by a small static electric field and a small hydrodynamic force, around a nonlinear Poisson–Boltzmann equilibrium with given surface charges of arbitrary size. This approach allows us to calculate the linear response regime in a way initially proposed by O’Brien. The O’Brien linearization requires a fast and accurate solution of the underlying Poisson–Boltzmann equation. We present an analysis of it, with the discussion of the boundary layer appearing as the Debye–Hückel parameter becomes large. Next, we briefly discuss the corresponding two-scale asymptotic expansion and reduce the obtained two-scale equations to a coarse scale model. Our previous rigorous study proves that the homogenized coefficients satisfy Onsager properties, namely they are symmetric positive definite tensors. We illustrate with numerical simulations several characteristic situations and discuss the behavior of the effective coefficients when the Debye–Hückel parameter is large. Simulated qualitative behavior differs significantly from the situation when the surface potential is given (instead of the surface charges). In particular, we observe the Donnan effect (exclusion of co-ions for small pores). 相似文献