Solution for a plane strain rough‐walled hydraulic fracture driven by turbulent fluid through impermeable rock          下载免费PDF全文

N. Zolfaghari  E. Dontsov  A. P. Bunger 《国际地质力学数值与分析法杂志》2018,42(4):587-617

The impact of turbulent flow on plane strain fluid‐driven crack propagation is an important but still poorly understood consideration in hydraulic fracture modeling. The changes that hydraulic fracturing has experienced over the past decade, especially in the area of fracturing fluids, have played a major role in the transition of the typical fluid regime from laminar to turbulent flow. Motivated by the increasing preponderance of high‐rate, water‐driven hydraulic fractures with high Reynolds number, we present a semianalytical solution for the propagation of a plane strain hydraulic fracture driven by a turbulent fluid in an impermeable formation. The formulation uses a power law relationship between the Darcy‐Weisbach friction factor and the scale of the fracture roughness, where one specific manifestation of this generalized friction factor is the classical Gauckler‐Manning‐Strickler approximation for turbulent flow in a rough‐walled channel. Conservation of mass, elasticity, and crack propagation are also solved simultaneously. We obtain a semianalytical solution using an orthogonal polynomial series. An approximate closed‐form solution is enabled by a choice of orthogonal polynomials embedding the near‐tip asymptotic behavior and thus giving very rapid convergence; a precise solution is obtained with 2 terms of the series. By comparison with numerical simulations, we show that the transition region between the laminar and turbulent regimes can be relatively small so that full solutions can often be well approximated by either a fully laminar or fully turbulent solution.  相似文献   

Modelling the poroelastoplastic behaviour of soils subjected to internal erosion by suffusion     

Quentin Rousseau  Giulio Sciarra  Rachel Gelet  Didier Marot 《国际地质力学数值与分析法杂志》2020,44(1):117-136

Granular soils subjected to seepage flow may suffer suffusion, ie, a selective internal erosion. Extending the classical approach of poromechanics, we deduce a new form of the Clausius-Duhem inequality accounting for dissipation due to suffusion, and we deduce restrictions on the constitutive laws of the soil. We suggest (a) a possible coupling between the seepage forces and the suffusion kinetics and (b) an extension of an existing elastoplastic model for the skeleton mechanical behaviour. Numerical integrations of the elastoplastic model are carried out under drained axisymmetric triaxial and oedometric conditions. As a result, we prove that the extended model is able to qualitatively reproduce the suffusion induced strains and the strength reduction experimentally observed. Predictions on the oedometric behaviour of suffusive soils are also provided.  相似文献   

A modified numerical model for moisture-salt transport in unsaturated sandy soil under evaporation     

Wei Wen  YuanMing Lai  ZheMin You 《寒旱区科学》2020,12(3):125-133

Soil salinization, caused by salt migration and accumulation underneath the soil surface, will corrode structures. To analyze the moisture-salt migration and salt precipitation in soil under evaporation conditions, a mathematical model consisting of a series of theoretical equations is briefly presented. The filling effect of precipitated salts on tortuosity factor and evaporation rate are taken into account in relevant equations. Besides, a transition equation to link the solute transport equation before and after salt precipitation is proposed. Meanwhile, a new relative humidity equation deduced from Pitzer ions model is used to modify the vapor transport flux equation. The results show that the calculated values are in good agreement with the published experimental data, especially for the simulation of volume water content and evaporation rate of Toyoura sand, which confirm the reliability and applicability of the proposed model.  相似文献   

Overview of In - Situ Biodegradation and Enhancement     

DONG Jun  Anthony Adzomani  Zhao Yongsheng 《世界地质(英文版)》2002,5(1)

Microbial degradation technologies have been developed to restore ground water quality in aquifers polluted by organic contaminants effectively in recent years. However, in course of the degradation, the formation of biofilms in ground water remediation technology can be detrimental to the effectiveness of a ground water remediation project. Several alternatives are available to a remedial design engineer, such as Permeable Reactive Barriers (PRBs) and in -situ bioremediation, Hydrogen Releasing Compounds (HRCs) barrier, Oxygen Releasing Compounds (ORCs) barrier etc. which are efficient and cost- effective technologies. Excessive biomass formation renders a barrier ineffective in degrading the contaminants, Efforts are made to develop kinetics models which accurately determine bio - fouling and bio - filn formation and to control excessive biomass formation.  相似文献   

Anisotropies in the redshift-space correlations of galaxy groups and clusters – I. Simulated catalogues     

N. D. Padilla  D. G. Lambas † 《Monthly notices of the Royal Astronomical Society》2003,342(2):519-531

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Ghosts of the Milky Way: a search for topology in new quasar catalogues     

S. J. Weatherley  S. J. Warren  S. M. Croom  R. J. Smith  B. J. Boyle  T. Shanks  L. Miller  M. P. Baltovic 《Monthly notices of the Royal Astronomical Society》2003,342(1):L9-L13

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High energy phenomena in eta carinae     

Roberto F. Viotti  Lucio Angelo Antonelli  Sonja Rebecchi  Corinne Rossi 《Journal of Astrophysics and Astronomy》2002,23(1-2):19-22

We have investigated with BeppoSAX the long term behaviour of the harder X-ray component of the supposed supermassive binary system η Car along its 5.52 year cycle. We have found that in March 1998 during egress from the last December 1997 eclipse, this component was the same as outside eclipse, but for a large (×3.5) increase of NH _h , that can be attributed to the presence or formation of opaque matter in front of the source near periastron. Unexpectedly, at that time the iron 6.7 keV emission line was 40% stronger. BeppoSAX has for the first time found ahard X-ray tail extending to at least 50 keV, that cannot be adequately fitted with an additional hotter thermal component. The 2–100 keV spectrum of η Car is instead well fitted with an absorbed powerlaw spectrum with photon index 2.53, suggesting non-thermal emission as an alternative model for the core source.  相似文献   

Cluster cross-sections for strong lensing: analytic and numerical lens models     

Massimo Meneghetti  Matthias Bartelmann  Lauro Moscardini † 《Monthly notices of the Royal Astronomical Society》2003,340(1):105-114

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SN 1999E: another piece in the supernova–gamma-ray burst connection puzzle     

L. Rigon  M. Turatto  S. Benetti  A. Pastorello  E. Cappellaro  I. Aretxaga  O. Vega  V. Chavushyan  F. Patat  I. J. Danziger  M. Salvo 《Monthly notices of the Royal Astronomical Society》2003,340(1):191-196

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Cluster lensing of quasars as a probe of ΛCDM and dark energy cosmologies     

Ana M. Lopes  Lance Miller 《Monthly notices of the Royal Astronomical Society》2004,348(2):519-528

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