Multiphase flow modeling with density functional method     

Oleg Dinariev  Nikolay Evseev 《Computational Geosciences》2016,20(4):835-856

This paper is a review of applications of density functional theory (DFT) in compositional hydrodynamics. The basic idea is representation of the entropy or the Helmholtz energy of the mixture as the functional depending on the molar densities of chemical components (density functional). The hydrodynamics is governed by local conservation laws of chemical components, momentum, and energy, while constitutive relations and boundary conditions are introduced in accordance with the explicit form of the density functional. The general ideas and the history of the DFT in compositional hydrodynamics are discussed. Then the DFT for multiphase multicomponent mixtures is presented including the exposition of the first principles, governing equations and constitutive relations, and explicit expressions of density functional depending on physical situation. The DFT-based numerical simulator is described, and several multiphase simulation results are presented to illustrate the scope and effectiveness of DFT: sessile drop with and without surfactant, droplet breakup in shear flow, and three-phase hydrodynamics with mobile solid phase. Also, two practical scenarios with multiphase simulations in micro-CT porous rock models are presented: two-phase immiscible water-oil flow and three-phase water-gas-condensate flow with phase transitions. All numerical results are obtained by essentially the same code; both the number of chemical components and the Helmholtz energy have been set up in accordance with physical situation.  相似文献   

Comment on Georgiev et al. “Structure and U–Pb zircon geochronology of an Alpine nappe stack telescoped by extensional detachment faulting (Kulidzhik area,Eastern Rhodopes,Bulgaria)     

Nikolay Bonev  Richard Spikings  Peter Marchev 《International Journal of Earth Sciences》2016,105(7):2161-2170

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State of the environment of urban and mining areas in the Selenga Transboundary River Basin (Mongolia Russia)     

Nikolay Kasimov  Natalia Kosheleva  Petr Gunin  Ilya Korlyakov  Olga Sorokina  Ivan Timofeev 《Environmental Earth Sciences》2016,75(18):1283

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Platinum-group minerals in the LG and MG chromitites of the eastern Bushveld Complex,South Africa     

Thomas Oberthür  Malte Junge  Nikolay Rudashevsky  Eveline de Meyer  Paul Gutter 《Mineralium Deposita》2016,51(1):71-87

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Natural Molecular Hydrogen Seepage Associated with Surficial,Rounded Depressions on the European Craton in Russia     

Nikolay Larin  Viacheslav Zgonnik  Svetlana Rodina  Eric Deville  Alain Prinzhofer  Vladimir N. Larin 《Natural Resources Research》2015,24(3):369-383

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Freshening of near-bottom waters in Lake Baikal triggered by the Mw6.2 Kultuk earthquake of August 2008     

Nikolay G. Granin  Natalia A. Radziminovich  Liba Z. Granina  Vadim V. Blinov  Ruslan Y. Gnatovskiy 《Geo-Marine Letters》2012,32(5-6):453-464

In September 2008, freshening of near-bottom water and an increase in concentration of suspended particles were observed in the western part of southern Lake Baikal. The reduction in the content of total dissolved solids was about 0.4–0.7?mg/kg (0.7?%), and average suspended particle concentration increased strongly to 6–9?mg/l, the background value being 0.2?mg/l. The spatial distribution of these waters was virtually identical to the focal area of the M_w6.2 Kultuk earthquake that occurred on 27 August 2008. It is suggested that there was a causal relationship between these two phenomena. Freshening of a significant amount (about 20?km³) of near-bottom waters was plausibly caused by an input of poorly mineralized pore waters from bottom sediments as a result of dissociation of methane gas hydrates suspected to occur in the area. The energy radiated by the earthquake source was four orders of magnitude smaller than that needed to explain the observed freshening of near-bottom waters. This points to other mechanisms leading to seismic-induced sediment failure and possible subsequent hydrate dissociation in the case of the Kultuk earthquake.  相似文献   

地球电磁法研究新进展——“第19届国际地球电磁感应学术研讨会”专辑   总被引：2，自引：1，他引：1       下载免费PDF全文

赵国泽  Nikolay Palshin  黄清华 《地球物理学报》2010,53(3):469-478

1 研讨会概况 地球电磁法是地球物理学的重要方法,它是通过观测自然的和人工产生的电场、磁场或电磁场研究自地表到地幔深处的电性结构和空间环境. 由IAGA I-2 工作组主办的两年一届的"国际地球电磁感应学术研讨会"的目的是展示和交流各种电磁方法的最新研究成果和前沿研究课题.每次研讨会的举办地点经过竞争和选举确定,1972年在Edinburgh, U.K.举行了第1届研讨会.  相似文献   

Impacts of stormwater runoff in the Southern California Bight: Relationships among plume constituents     

Kristen M. Reifel  Scott C. Johnson  Paul M. DiGiacomo  Michael J. Mengel  Nikolay P. Nezlin  Jonathan A. Warrick  Burton H. Jones 《Continental Shelf Research》2009,29(15):1821-1835

The effects from two winter rain storms on the coastal ocean of the Southern California Bight were examined as part of the Bight ‘03 program during February 2004 and February–March 2005. The impacts of stormwater from fecal indicator bacteria, water column toxicity, and nutrients were evaluated for five major river discharges: the Santa Clara River, Ballona Creek, the San Pedro Shelf (including the Los Angeles, San Gabriel, and Santa Ana Rivers), the San Diego River, and the Tijuana River. Exceedances of bacterial standards were observed in most of the systems. However, the areas of impact were generally spatially limited, and contaminant concentrations decreased below California Ocean Plan standards typically within 2–3 days. The largest bacterial concentrations occurred in the Tijuana River system where exceedances of fecal indicator bacteria were noted well away from the river mouth. Maximum nitrate concentrations (~40 μM) occurred in the San Pedro Shelf region near the mouth of the Los Angeles River. Based on the results of general linear models, individual sources of stormwater differ in both nutrient concentrations and the concentration and composition of fecal indicator bacteria. While nutrients appeared to decrease in plume waters due to simple mixing and dilution, the concentration of fecal indicator bacteria in plumes depends on more than loading and dilution rates. The relationships between contaminants (nutrients and fecal indicator bacteria) and plume indicators (salinity and total suspended solids) were not strong indicating the presence of other potentially important sources and/or sinks of both nutrients and fecal indicator bacteria. California Ocean Plan standards were often exceeded in waters containing greater than 10% stormwater (<28–30 salinity range). The median concentration dropped below the standard in the 32–33 salinity range (1–4% stormwater) for total coliforms and Enterococcus spp. and in the 28–30 salinity range (10–16% stormwater) for fecal coliforms. Nutrients showed a similar pattern with the highest median concentrations in water with greater than 10% stormwater. Relationships between colored dissolved organic matter (CDOM) and salinity and between total suspended solids and beam attenuation indicate that readily measurable, optically active variables can be used as proxies to provide at least a qualitative, if not quantitative, evaluation of the distribution of the dissolved, as well as the particulate, components of stormwater plumes. In this context, both CDOM absorption and the beam attenuation coefficient can be derived from satellite ocean color measurements of inherent optical properties suggesting that remote sensing of ocean color should be useful in mapping the spatial areas and durations of impacts from these contaminants.  相似文献   

Climate extremes in South Western Siberia: past and future   总被引：1，自引：1，他引：0  

Degefie T. Degefie  Elisa Fleischer  Otto Klemm  Andrey V. Soromotin  Olga V. Soromotina  Andrey V. Tolstikov  Nikolay V. Abramov 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(8):2161-2173

In this study, the temporal and spatial trends of ten climate extreme indices were computed based on observed daily precipitation and on daily maximum and minimum temperatures at 26 weather stations in South Western Siberia during the period 1969–2011 and, based on projected daily maximum and minimum temperatures, during 2021–2050. The Mann–Kendall test was employed to analyze the temporal trend and a combination of multiple linear regressions and semivariogram functions were used to evaluate the regional spatial trends and the local spatial variability of climate extremes, respectively. The results show that the temperature-based climate extremes increase at a 0.05 significance level while none of the precipitation-based climate extremes did. Spatially, dominant gradients are observed along latitude: The northern taiga vegetation zone experiences a colder and wetter climate while the southern forest steppe zone is drier and hotter. Over time, a tendency towards homogenization of the regional climate is observed through a decrease of the spatial variability for most climate extreme indices. In the future, the most intense changes are anticipated for the bio-climate indicators “growing season length” and “growing degree days” in the north, while the warming indicators, “warm day” and “warm night” are expected to be high to the south.  相似文献   

Modelling the wave phenomena in acoustic and elastic media with sharp variations of physical properties using the grid‐characteristic method          下载免费PDF全文

Alena V. Favorskaya  Michael S. Zhdanov  Nikolay I. Khokhlov  Igor B. Petrov 《Geophysical Prospecting》2018,66(8):1485-1502

This paper introduces a novel method of modelling acoustic and elastic wave propagation in inhomogeneous media with sharp variations of physical properties based on the recently developed grid‐characteristic method which considers different types of waves generated in inhomogeneous linear‐elastic media (e.g., longitudinal, transverse, Stoneley, Rayleigh, scattered PP‐, SS‐waves, and converted PS‐ and SP‐waves). In the framework of this method, the problem of solving acoustic or elastic wave equations is reduced to the interpolation of the solutions, determined at earlier time, thus avoiding a direct solution of the large systems of linear equations required by the FD or FE methods. We apply the grid‐characteristic method to compare wave phenomena computed using the acoustic and elastic wave equations in geological medium containing a hydrocarbon reservoir or a fracture zone. The results of this study demonstrate that the developed algorithm can be used as an effective technique for modelling wave phenomena in the models containing hydrocarbon reservoir and/or the fracture zones, which are important targets of seismic exploration.  相似文献