228,277 research outputs found
Integral representation of a solution to the Stokes-Darcy problem
No full textWith methods of potential theory we develop a representation of a solution of the coupled Stokes-Darcy model in a Lipschitz domain for boundary data in H-1/2
Elizabeth Darcy
No full textElizabeth was the second child of Elizabeth and James Walden. In 1912 Elizabeth married John William Hopkins. They had two children, Adelaide (Alice) and William Walter. Elizabeth's husband died in September 1918.
Elizabeth married George John Darcy after he escorted her to her mother after her first husband's death.
Elizabeth and George had 12 children including two sets of twins. When they moved to Mallapunyah Springs, Elizabeth built the house, furniture and toys while her husband was away earning money.
Elizabeth was also the family's teacher, as education was provided through correspondence from Camooweal.
Elizabeth contacted the Department of Lands for their leases of land of approximately 4077 square kilometres. Although her husband would eventually work prominently on their land, Elizabeth proved she was as physically capable to work along side him, and still maintain the house hold.
Elizabeth is also remembered for her positive attitude towards the local indigenous communities and her welcomed medical advice particular to new mothers.
On 31 October 1944, Elizabeth and her son Mick did not return home while looking for donkeys. The search was offically abandoned on 29 November with the entry in the Police Journal reading as follows: "Despite combined efforts 10 whites and 30 Aboriginals, no trace of Mrs Darcy or son can be found.Has been suggested they caught quiet grey horse and rode away nevertheless I fear they have perished in rough hilly country south Mallapunyah where water limited. Have abandoned search."ManagerTeacherHouse dutiesBuilderHorse-breake
A symmetric nodal conservative finite element method for the Darcy equation
No full textThis work introduces and analyzes novel stable Petrov-Galerkin EnrichedMethods (PGEM) for the Darcy problem based on the simplest but unstable continuous P1/P0 pair. Stability is recovered inside a Petrov-Galerkin framework where element-wise dependent residual functions, named multi-scale functions, enrich both velocity and pressure trial spaces. Unlike the velocity test space that is augmented with bubble-like functions, multi-scale functions correct edge residuals as well. The multi-scale functions turn out to be the well-known lowest order Raviart-Thomas basis functions for the velocity and discontinuous quadratics polynomial functions for the pressure. The enrichment strategy suggests the way to recover the local mass conservation property for nodal-based interpolation spaces. We prove that the method and its symmetric version are well-posed and achieve optimal error estimates in natural norms. Numerical validations confirm claimed theoretical results
Darcy-Forchheimer flow of MHD free convective CNTs Casson nanoliquid via a cosinusoidally fluctuating heated plate
No full textThis study explores the influence of carbon nanotubes (CNTs), spanwise cosinusoidally fluctuating thermal and mass diffusion on unsteady MHD free convective flow of Casson nanoliquid via an infinite hot vertical porous plate in a Darcy-Forchheimer porous medium. The overlapping grid multi-domain trivariate spectral collocation method is used to solve the non-dimensional equations. The impact of varying physical estimators on profiles alongside skin friction factor, rate of heat, and mass transport is contemplated. It was disclosed that the velocity and skin friction factors can be maximized via strong buoyancy forces and porous permeability but minimized through strong magnetic field and the Darcy–Forchheimer relation. The temperature and rate of heat transport can be increased by higher levels of heat generation, viscous dissipation, diffusion-thermo, and radiation absorption. Conversely, these factors can be minimized with higher thermal radiation. The introduction of activation energy and nonlinear chemically reactive species is responsible for the increase in species concentration and the rate of mass transport. The velocity and temperature are enhanced with increasing CNTs volume fraction, which leads to an increment in skin friction factor and thermal transport rate. Therefore, the suspension of CNTs in conventional fluids to control the coolant level in industrial apparatuses is absolutely practical.</p
Lordship and patronage: John Darcy and the Dublin administration 1324-47
No full textJohn Darcy rose from being a landless member of a cadet branch of a minor Lincolnshire family to serve as steward and chamberlain in the king's household. Justiciar of Ireland for twelve years m total, he developed close links with both Edward II and Edward III, surviving changes of regime in England in 1326 and in 1330, and served as one of the king's captains in Scotland and France. He acquired property in the north Midlands, and in Ireland, where he married into the comital house of de Burgh. This thesis examines his career as justiciar, steward, and chamberlain, exploring how it illustrates the search for, and provision of, 'good lordship'. It assesses whether his friends and associates benefited from his influential position. The personnel of the Dublin government - judicial courts, chancery, exchequer, customs, escheatry, and royal constables - are investigated to discover the impact of Darcy upon appointments. This is set in the context of the influence of other chief governors and that of other evident patterns of patronage within the administration. To do this effectively, the diesis is divided into two parts. The first part surveys Darcy’s career, while in the second half, the Dublin administration is examined by department, commencing with the offices over which Darcy exercised most influence, before following a more conventional hierarchical approach. The thesis concludes by assessing the implications of the influence of Darcy and others upon the relationship of the lordship of Ireland and the kingdom of England
Drawn Together by M. Le
No full textLe, Minh. Drawn Together. Illustrated by Dan Santat, Disney Hyperion, 2018. Drawn Together is a work of art created by Minh Le, author of award winning, Let Me Finish!, and illustrated by Caldecott Medalist, Dan Santat. This beautiful story depicts the cultural and linguistic divide between a young boy and his grandfather. The book invites the reader to walk alongside these two characters as they struggle with their differences only to stumble upon their similarities. Bringing together two generations of artists, the story revels in the characters’ imaginations as they create a vivid world of artistic adventures and compassion. Inhibited by the linguistic barriers that once isolated the characters, Minh Le’s limited, yet well crafted, text serves to support Dan Santat’s captivating illustrations that “draw” the grandfather and young boy closer. Detailed facial expressions and rich illustrations heighten the reading experience and weave together a story that both literally and metaphorically bridges the space between a grandfather and his grandson. Whether you are curling up with young ones at home or searching for a beautiful book for your classroom library, look no further. This one is guaranteed to draw you in! Highly recommended: 4 out of 4 StarsReviewer: Darcy Courtland Darcy Courtland loves a good picture book! After seven years in the classroom, Darcy has returned to the University of Alberta to pursue a PhD in Elementary Education. Always up for a new adventure, Darcy is excited to be furthering her education in language and literacy and Indigenous education
A two-level enriched finite element method for a mixed problem
No full textThe simplest pair of spaces is made inf-sup stable for the mixed form of the Darcy equation. The key ingredient is to enhance the finite element spaces inside a Petrov-Galerkin framework with functions satisfying element-wise local Darcy problems with right hand sides depending on the residuals over elements and edges. The enriched method is symmetric, locally mass conservative and keeps the degrees of freedom of the original interpolation spaces. First, we assume local enrichments exactly computed and we prove uniqueness and optimal error estimates in natural norms. Then, a low cost two-level finite element method is proposed to effectively obtain enhancing basis functions. The approach lays on a two-scale numerical analysis and shows that well-posedness and optimality is kept, despite the second level numerical approximation. Several numerical experiments validate the theoretical results and compares (favourably in some cases) our results with the classical Raviart-Thomas elemen
Effects of non-Darcy flow on pressure buildup analysis of hydraulically fractured gas reservoirs
No full textDue to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 86-88).Issued also on microfiche from Lange Micrographics.Conventional well-testing techniques are commonly used to evaluate pressure transient tests of hydraulically fractured wells to estimate values such as formation permeability, fracture length, and fracture conductivity. When non-Darcy flow occurs along the fracture, analysis of the pressure transient test using conventional analysis methods will produce incorrect values of fracture conductivity and fracture half-length. The objective of this project is to emphasize the importance of non-Darcy flow in the hydraulic fracture and its effects on pressure buildup analysis of hydraulically fractured gas reservoirs. A reservoir simulator was used to generate pressure drawdown and buildup data both with and without the effects of non-Darcy flow. These synthetic buildup tests were then analyzed using conventional well-testing techniques. It was found that when non-Darcy flow occurs along the fracture, the estimated fracture conductivity and fracture half-length represent only a small fraction of the actual values. Also, the degree to which the non-Darcy flow affects the well-test results depends upon the values of fracture permeability, water saturation inside the fracture, and the production rate during the drawdown period. If the incorrect fracture properties obtained from conventional analysis are used in reservoir simulation forecasting, critical values such as production rate and total recovery will be miscalculated. Since conventional well-test analysis cannot be used to determine fracture parameters reliably, simulation history matching is the appropriate method to correctly analyze buildup pressure response from hydraulically fractured reservoirs with significant non-Darcy flow effects
Optimal fracture treatment design for dry gas wells maximizes well performance in the presence of non-Darcy flow effects
No full textThis thesis presents a methodology based on Proppant Number approach for optimal fracture treatment design of natural gas wells considering non-Darcy flow effects in the design process. Closure stress is taken into account, by default, because it is the first factor decreasing propped pack permeability at in-situ conditions. Gel damage was also considered in order to evaluate the impact of incorporating more damaging factors on ultimate well performance and optimal geometry. Effective fracture permeability and optimal fracture geometry are calculated through an iterative process. This approach was implemented in a spreadsheet.
Non-Darcy flow is described by the �� factor. All �� factor correlations available in the literature were evaluated. It is recommended to use the correlation developed specifically for the given type of proppant and mesh size, if available. Otherwise, the Pursell et al. or the Martins et al. equations are recommended as across the board reliable correlations for predicting non-Darcy flow effects in the propped pack.
The proposed methodology was implemented in the design of 11 fracture treatments of 3 natural tight gas wells in South Texas. Results show that optimal fracture design might increase expected production in 9.64 MMscf with respect to design that assumes Darcy flow through the propped pack. The basic finding is that for a given amount of proppant shorter and wider fractures compensate the non-Darcy and/or gel damage effect.
Dynamic programming technique was implemented in design of multistage fractures for one of the wells under study for maximizing total gas production. Results show it is a powerful and simple technique for this application. It is recommended to expand its use in multistage fracture designs
The impact of gravity segregation on multiphase non-Darcy flow in hydraulically fractured gas wells
No full textMultiphase and non-Darcy flow effects in hydraulically fractured gas wells reduce
effective fracture conductivity. Typical proppant pack laboratory experiments are
oriented in such a way such that phase segregation is not possible, which results in
mixed flow. Tidwell and Parker (1996), however, showed that in proppant packs, gravity
segregation occurs for simultaneous gas and liquid injection at laboratory scale (1500
cm2). Although the impact of gravity on flow in natural fractures has been described,
previous work has not fully described the effect of gravity on multiphase non-Darcy
flow in hydraulic fractures. In this work, reservoir simulation modeling was used to
determine the extent and impact of gravity segregation in a hydraulic fracture at field
scale. I found that by ignoring segregation, effective fracture conductivity can be
underestimated by up to a factor of two.
An analytical solution was developed for uniform flux of water and gas into the fracture.
The solution for pressures and saturations in the fracture agrees well with reservoir
simulation. Gravity segregation occurs in moderate-to-high conductivity fractures. Gravity segregation impacts effective fracture conductivity when gas and liquid are
being produced at all water-gas ratios modeled above 2 Bbls per MMscf. More realistic,
non-uniform-flux models were also run with the hydraulic fracture connected to a gas
reservoir producing water. For constant-gas-rate production, differences in pressure
drop between segregated cases and mixed flow cases range up to a factor of two. As the
pressure gradient in the fracture increases above 1 to 2 psi/ft, the amount of segregation
decreases. Segregation is also less for fracture half-length-to-height ratios less than or
close to two. When there is less segregation, the difference in effective conductivity
between the segregated and mixed flow cases is reduced. I also modeled the water
injection and cleanup phases for a typical slickwater fracture treatment both with and
without gravity effects and found that for cases with segregation, effective fracture
conductivity is significantly higher than the conductivity when mixed flow occurs.
Gravity segregation is commonly ignored in design and analysis of hydraulically
fractured gas wells. This work shows that segregation is an important physical process
and it affects effective fracture conductivity significantly. Hydraulic fracture treatments
can be designed more effectively if effective fracture conductivity is known more
accurately
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