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Journal articleBrito-Parada PR, Kramer SC, Wilson CR, et al., 2012,
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Journal articleBrito-Parada PR, Neethling SJ, Cilliers JJ, 2012, , Minerals Engineering, Vol: 33, Pages: 80-86
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Journal articleSaunders JH, Jackson MD, Pain CC, et al., 2012, , Geophysics, Vol: 77, Pages: E77-E90
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Journal articleHill J, Piggott MD, Ham DA, et al., 2012, , Ocean Modelling, Vol: 56, Pages: 1-15
Research into the use of unstructured mesh methods for ocean modelling has been growing steadily in the last few years. One advantage of using unstructured meshes is that one can concentrate resolution where it is needed. In addition, dynamic adaptive mesh optimisation (DAMO) strategies allow resolution to be concentrated when this is required. Despite the advantage that DAMO gives in terms of improving the spatial resolution where and when required, small-scale turbulence in the oceans still requires parameterisation. A two-equation, generic length scale (GLS) turbulence model (one equation for turbulent kinetic energy and another for a generic turbulence length-scale quantity) adds this parameterisation and can be used in conjunction with adaptive mesh techniques. In this paper, an implementation of the GLS turbulence parameterisation is detailed in a non-hydrostatic, finite-element, unstructured mesh ocean model, Fluidity-ICOM. The implementation is validated by comparing to both a laboratory-scale experiment and real-world observations, on both fixed and adaptive meshes. The model performs well, matching laboratory and observed data, with resolution being adjusted as necessary by DAMO. Flexibility in the prognostic fields used to construct the error metric used in DAMO is required to ensure best performance. Moreover, the adaptive mesh models perform as well as fixed mesh models in terms of root mean square error to observation or theoretical mixed layer depths, but uses fewer elements and hence has a reduced computational cost.
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Conference paperBaker CMJ, Buchan AG, Pain CC, et al., 2011,
Anisotropic mesh adaptivity for eigenvalue calculations using energy dependent meshes
, International Conference in Nuclear Criticalit -
Conference paperBuchan AG, Pain CC, Eaton MD, et al., 2011,
Dynamics and heat transfer characteristics of the water boiler reactor - SUPO
, International Conference in Nuclear Criticality -
Conference paperBuchan AG, Pain CC, Eaton MD, et al., 2011,
Simulated spatially dependent transient kinetics analysis of the oak ridge Y12 Plant criticality excursion, International Conference in Nuclear Criticality
, International Conference in Nuclear Criticality -
Journal articleSouthern J, Gorman GJ, Piggott MD, et al., 2011, , Journal of Computational Science, Vol: 3, Pages: 8-16
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Journal articleCollins GS, Elbeshausen D, Davison TM, et al., 2011, , Earth and Planetary Science Letters, Vol: 310, Pages: 1-8, ISSN: 0012-821X
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Journal articleDavison TM, Collins GS, Elbeshausen D, et al., 2011, , METEORITICS & PLANETARY SCIENCE, Vol: 46, Pages: 1510-1524, ISSN: 1086-9379
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- Citations: 75
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Journal articleMorris GDM, Neethling SJ, Cilliers JJ, 2011, , LANGMUIR, Vol: 27, Pages: 11475-11480, ISSN: 0743-7463
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- Citations: 15
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Journal articleMorris G, Neethling SJ, Cilliers JJ, 2011, , JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 361, Pages: 370-380, ISSN: 0021-9797
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- Citations: 20
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Journal articleJackson MD, Vinogradov J, Saunders JH, et al., 2011, , SPE JOURNAL, Vol: 16, Pages: 625-636, ISSN: 1086-055X
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- Citations: 10
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Journal articleNeethling SJ, Morris GDM, Garrett PR, 2011, , Langmuir
It is widely known that oil droplets can decrease the stability ofaqueous films and foams. While less widely recognized, it has also beenobserved that oil droplets can, under certain circumstances, increase thestability of foams, especially if they are caught in the Plateau borders. In thispaper, how the oil droplet deforms and is, in turn, deformed by the Plateauborder is modeled using Surface Evolver. The two dimensionless parametersthat affect these shapes are the size of the oil droplet relative to the Plateauborder and the ratio of the oil water interfacial tension to the air waterinterfacial tension. The calculated pressures in all the phases were used toobtain the pressure exerted on the oil water air pseudoemulsion film, whichallows the factors that influence the stability of these droplets in the Plateauborder to be investigated. The final section of the paper demonstrates that thepresence of an oil droplet in a Plateau border can have a major influence on thedrainage of the aqueous phase along the Plateau border. This retardation of the flow would result in the oil droplets in the Plateauborders increasing the stability of foams in which they are found.
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Journal articleGomes JLMA, Pain CC, Eaton MD, et al., 2011, , PROGRESS IN NUCLEAR ENERGY, Vol: 53, Pages: 523-552, ISSN: 0149-1970
Investigation of nuclear criticality in powder systems is necessary for the assessment of industrial plant integrity and potential radiation impacts on worker and the public health. For nuclear fuel processing, to produce fuel pellets, MOX (UO2 + PuO2) and zinc stearate (lubricant) powders are homogenised in a stirred vessel. The coupled multi-fluids (multiphase and multi-component) and neutron-radiation transport FETCH model was extended to simulate reactivity feedback mechanisms and to assess safety and potential risks of criticality incursions in 2-3D systems. This work has strengthened links with the Japan Atomic Energy Agency (JAEA), led to consultancy work with Japanese National Labs and work with Tokyo University that led on to the Todai Forum and the core to core program with Japan.
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Conference paperDavison TM, Ciesla FJ, Collins GS, 2011,
Quantification of the post-impact thermal evolution of planetesimals
, 74th Annual Meeting of the Meteoritical-Society, Publisher: Wiley-Blackwell, Pages: A53-A53, ISSN: 1086-9379 -
Conference paperCollins GS, Davison TM, Ciesla FJ, 2011,
The effects of planetesimal collisions
, 74th Annual Meeting of the Meteoritical-Society, Publisher: Wiley-Blackwell, Pages: A46-A46, ISSN: 1086-9379 -
Conference paperBland PA, Muxworthy AR, Collins GS, et al., 2011,
Heterogeneous shock in porous chondrites: Implications for Allende magnetization
, 74th Annual Meeting of the Meteoritical-Society, Publisher: Wiley-Blackwell, Pages: A22-A22, ISSN: 1086-9379 -
Conference paperMiljkovic K, Mannick S, Collins GS, et al., 2011,
HYDROCODE SIMULATIONS OF BINARY ASTEROID IMPACTS
, 74th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A161-A161, ISSN: 1086-9379 -
Journal articleWang H, Colvile RN, Pain C, et al., 2011, , TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT, Vol: 16, Pages: 392-401, ISSN: 1361-9209
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- Citations: 5
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Journal articleArdjmandpour N, Pain C, Singer J, et al., 2011, , GEOPHYSICAL PROSPECTING, Vol: 59, Pages: 721-748, ISSN: 0016-8025
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- Citations: 11
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Journal articleWozniakiewicz PJ, Ishii HA, Kearsley AT, et al., 2011, , METEORITICS & PLANETARY SCIENCE, Vol: 46, Pages: 1007-1024, ISSN: 1086-9379
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- Citations: 25
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Journal articleGulamali MY, Leinov E, Jackson MD, 2011, , Geophysics, Vol: 76, Pages: F283-F292, ISSN: 1942-2156
The injection of cold water into a hydrocarbon reservoir containingrelatively warmer, more saline formation brine may generateself-potential anomalies as a result of electrokinetic,thermoelectric, and=or electrochemical effects. We havenumerically assessed the relative contributions of these effectsto the overall self-potential signal generated during oil productionin a simple hydrocarbon reservoir model. Our aim was todetermine if measurements of self-potential at a production wellcan be used to detect the movement of water toward the well.The coupling coefficients for the electrochemical and thermoelectricpotentials are uncertain, so we considered four differentmodels for them. We also investigated the effect of altering thesalinities of the formation and injected brines. We found thatthe electrokinetic potential peaked at the location of the saturationfront (reaching values of 0.2 mV even for the most salinebrine considered). Moreover, the value at the production wellincreased as the front approached the well, exceeding the noiselevel ( 0.1 mV). Thermoelectric effects gave rise to largerpotentials in the reservoir (10 mV), but values at the wellwere negligible ð Þ .0:1 mV until after water breakthroughbecause of the lag in the temperature front relative to the saturationfront. Electrochemical potentials were smaller in magnitudethan thermoelectric potentials in the reservoir but were measurableð Þ > 0:1 mV at the well because the salinity front wasclosely associated with the saturation front. When the formationbrine was less saline (1 mol=liter), electrokinetic effects dominated;at higher salinities (5 mol=liter), electrochemicaleffects were significant. We concluded that the measurement ofself-potential signals in a production well may be used to monitorthe movement of water in hydrocarbon reservoirs duringproduction, but further research is required to understand thethermoelectric and electrochemical coupling coefficients in partiallysatu
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Journal articleDavies DR, Wilson CR, Kramer SC, 2011, , GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, Vol: 12
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- Citations: 99
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Journal articleRan L, Jones SA, Embley B, et al., 2011, , COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol: 382, Pages: 50-57, ISSN: 0927-7757
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- Citations: 8
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Journal articleTong M, Cole KE, Neethling SJ, 2011, , Colloids and Surfaces A: Physicochemical and Engineering Aspects
An integrated numerical model was developed to predict the spatial and temporal evolution of the bubble size distribution within foams. In order to validate the modelling, experiments in a vertical pseudo-2D Hele-Shaw cell were carried out since the bubble size distribution in this system can be readily measured. The model combines a population balance sub-model for predicting the bubble size with a liquid drainage sub-model. The liquid drainage model is a version of the standard foam drainage equation that has been modified to account for a pseudo-2D geometry. It has also been modified to account for the confined shape of the bubble and the size of the gap between the vessel walls, as well as the different Plateau border shapes and orientations found in this system. The population balance model is used to predict the change of bubble size as films fail and bubbles coalesce. The population balance and liquid drainage models are fully coupled, with the bubble size distribution influencing the drainage and the capillary pressure exerted by the Plateau borders influencing coalescence. In order to validate this integrated numerical model, the size of bubbles in a rising pseudo-2D foam was measured with image analysis. The numerical model reasonably predicted the evolution of the mean bubble size and was in strong agreement with the bubble size distribution over the depth of the pseudo-2D foam. The predictions are very close to the measured experimental data.
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Journal articleCollins GS, Melosh HJ, Wunnemann K, 2011, , INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, Vol: 38, Pages: 434-439, ISSN: 0734-743X
We describe improvements to the epsilon-alpha porous compaction model for simulating solar system impacts. To improve the treatment of highly porous materials, we modified the epsilon-alpha model to account for thermal expansion of the matrix during compaction. We validated the improved model by demonstrating good agreement between numerically computed Hugoniot curves for porous iron (up to initial porosities of similar to 80%) using the improved epsilon-alpha model and experimentally-derived Hugoniot data. Moreover, we verified that the model improvements are easily implemented into a hydrocode and preserve the efficiency advantage of a strain-based compaction function. We used the improved epsilon-alpha porous compaction model in the iSALE hydrocode to reproduce 2-km/s porous-target laboratory impact experiments. The simulation results were in qualitative agreement with the experiments but produced craters that were consistently deeper and larger in volume than the experiments. The results of the hydrocode simulations and laboratory experiments show a reduction in crater efficiency with increasing porosity. This reduction is more dramatic if the impactor density and velocity are higher. (C) 2010 Elsevier Ltd. All rights reserved.
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Conference paperMerton SR, Smedley-Stevenson RP, Pain CC, et al., 2011,
An Adjoint Based Scheme for Eigenvalue Error Improvement
, International Conference on Mathematics, Computational Methods & Reactor Physics -
Journal articleBuchan AG, Merton SR, Pain CC, et al., 2011, , ANNALS OF NUCLEAR ENERGY, Vol: 38, Pages: 1186-1195, ISSN: 0306-4549
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- Citations: 20
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Journal articleDeveugle PEK, Jackson MD, Hampson GJ, et al., 2011, , AAPG Bulletin, Vol: 95, Pages: 693-727, ISSN: 0149-1423
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Journal articleHiester H, Piggott MD, Allison PA, 2011, , Ocean Modelling, ISSN: 1463-5003
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Journal articleMorris G, Neethling SJ, Cilliers JJ, 2011, , JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 354, Pages: 380-385, ISSN: 0021-9797
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- Citations: 33
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Conference paperNelson R, Piggott M, Wilson C, et al., 2011,
Compressible Flows on Adaptive and Unstructured Meshes with FLUIDITY
, 6th International Conference on Fluid Mechanics, Publisher: AMER INST PHYSICS, ISSN: 0094-243X -
Journal articleRatcliffe A, Win C, Vinje V, et al., 2011, , Seg Technical Program Expanded Abstracts, Vol: 30, Pages: 2384-2388, ISSN: 1052-3812
Full Waveform Inversion (FWI) aims to obtain superior velocity models by minimizing the difference between observed and modelled seismic waveforms. We apply FWI to a North Sea OBC field data set with wide azimuths and more than 10 km long offsets. We discuss the methodology used and the associated practical issues. Our FWI result has revealed detailed velocity features associated with thin, gas-charged layers and faulting in the shallow sections of the model. We demonstrate that this velocity update has improved the imaging of the deeper structures. © 2011 Society of Exploration Geophysicists.
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Conference paperBrito-Parada PR, Cilliers JJ, 2011,
3D modelling and experimental studies of flotation cell configurations for a two-phase system
, Flotation'11 -
Conference paperCole KE, Brito-Parada PR, Neethling SJ, et al., 2011,
A model of froth motion to test crowder designs - experimental validation with overflowing 2D foam
, Flotation'11 -
Journal articleFunke SW, Pain CC, Kramer SC, et al., 2011,
A wetting and drying algorithm with a combined pressure/free-surface formulation for non-hydrostatic models
, Advances in Water Resources -
Book chapterAllison PA, Bottjer DJ, 2011, , Taphonomy: Process and Bias Through Time (Volume 32 in the Topics in Geobiology series), Editors: Allison, Bottjer, Publisher: Springer, Pages: 1-18, ISBN: 978-90-481-8642-6
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Journal articleVinogradov J, 2011, , Geophysical Research Letters
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Book chapterBrett CE, Allison PA, Hendy AJW, 2011, , Taphonomy: Bias and Process Through Time (Volume 32 in the Topics in Geobiology series), Editors: Allison, Bottjer, Publisher: Springer, Pages: 107-198, ISBN: 978-90-481-8642-6
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Conference paperCilliers JJ, Brito-Parada PR, Cole KE, et al., 2011,
Advances in flotation using positron emission particle tracking and 3D simulation
, Procemin -
Conference paperRokos G, Gorman G, Kelly PHJ, 2011,
Accelerating Anisotropic Mesh Adaptivity on nVIDIA's CUDA Using Texture Interpolation
, 17th International Euro-Par Conference on Parallel Processing, Publisher: SPRINGER-VERLAG BERLIN, Pages: 387-398, ISSN: 0302-9743- Cite
- Citations: 1
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Conference paperLatham J-P, Xiang J, Harrison JP, et al., 2011,
Development of Virtual Geoscience Simulation Tools, VGeST for irregular blocky rock applications in rock engineering using the combined finite discrete element method, FEMDEM
, 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Publisher: Curran Associates, Pages: 965-976 -
Conference paperxiang J, Latham J-P, Harrison JP, 2011,
A Numeric Simulation of Rock Avalanches Using the Combined Finite-Discrete Element Method,FEMDEM
, 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Pages: 921-927 -
Conference paperHarrison JP, Xiang J, Latham JP, 2011,
Stress Heterogeneity in a Fractured Rock Mass Modelled with the Combined Finite-DiscreteElement Method
, 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Pages: 1051-1056 -
Conference paperLatham J-P, Xiang J, 2011,
A numerical investigation of the influence of friction and vibration on laboratory scale armour unit layers
, 6th International Conference on Coastal Structures, Publisher: World Scientific Publishing Company Pte Ltd. -
Conference paperXiang J, Latham J-P, Zimmer D, et al., 2011,
Modelling breakwater armour layers and the dynamic response of armour units.
, 6th International Conference on Coastal Structures -
Conference paperMilthaler F, Xiang J, Pavlidis D, et al., 2011,
The immersed body method combined with mesh adaptivity for solid-fluid coupling
, 6th International Conference on Coastal Structures -
Conference paperLatham J-P, Guo L, Wang X, 2011,
Modelling the Evolution of Fractures using a Combined FEMDEM Numerical Method
, 12th International Congress on Rock Mechanics, Harmonising Rock Engineering and the Environment, Publisher: ISRM Digital Library, One Petro -
Journal articleFang F, Pain CC, Navon IM, et al., 2011, , International Journal for Numerical Methods in Fluids, Vol: In review
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