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Journal articleCotter CJ, Ham DA, Pain CC, et al., 2009,
LBB stability of a mixed Galerkin finite element pair for fluid flow simulations
, Journal of Computational Physics, Vol: 228, Pages: 336-348We introduce a new mixed finite element for solving the 2- and 3-dimensional wave equations and equations of incompressible flow. The element, which we refer to as P1D–P2, uses discontinuous piecewise linear functions for velocity and continuous piecewise quadratic functions for pressure. The aim of introducing the mixed formulation is to produce a new flexible element choice for triangular and tetrahedral meshes which satisfies the LBB stability condition and hence has no spurious zero-energy modes. The advantage of this particular element choice is that the mass matrix for velocity is block diagonal so it can be trivially inverted; it also allows the order of the pressure to be increased to quadratic whilst maintaining LBB stability which has benefits in geophysical applications with Coriolis forces. We give a normal mode analysis of the semi-discrete wave equation in one dimension which shows that the element pair is stable, and demonstrate that the element is stable with numerical integrations of the wave equation in two dimensions, an analysis of the resultant discrete Laplace operator in two and three dimensions on various meshes which shows that the element pair does not have any spurious modes. We provide convergence tests for the element pair which confirm that the element is stable since the convergence rate of the numerical solution is quadratic.
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Journal articleXiang J, Munjiza A, Latham JP, et al., 2009,
On the validation of DEM and FEM/DEM models in 2D and 3D
, Engineering Computations, Vol: 26, Pages: 673-687, ISSN: 0264-4401 -
Journal articleLatham J-P, Mindel JE, Xiang J, et al., 2009,
Coupled FEMDEM/Fluids for coastal engineers with special reference to armour stability and breakage
, Geomechanics and Geoengineering, Vol: 4, Pages: 797-805 -
Journal articleFang F, Pain CC, Navon IM, et al., 2009,
A POD reduced order unstructured mesh ocean modelling method for moderate Reynolds number flows Ocean Modelling
, Ocean Modelling, Vol: 28, Pages: 127-136 -
Journal articleMunjiza A, Xiang J, Garcia X, et al., 2009,
The Virtual Geoscience Workbench, VGW: Open Source tools for discontinuous systems
, Particuology, Vol: in press -
Journal articleNeethling SJ, Cilliers JJ, 2008,
Predicting and correcting grade-recovery curves: Theoretical aspects
, INTERNATIONAL JOURNAL OF MINERAL PROCESSING, Vol: 89, Pages: 17-22, ISSN: 0301-7516- Author Web Link
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- Citations: 17
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Journal articleNeethling SJ, 2008,
Simple approximations for estimating froth recovery
, INTERNATIONAL JOURNAL OF MINERAL PROCESSING, Vol: 89, Pages: 44-52, ISSN: 0301-7516- Author Web Link
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- Citations: 26
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Journal articleAllison PA, Hesselbo SP, Brett CE, 2008,
Methane seeps on an Early Jurassic dysoxic seafloor
, Palaeogeography, Palaeoclimatology, Palaeoecology, Vol: 270, Pages: 230-238, ISSN: 0031-0182 -
Journal articleBosence DWJ, Allison PA, 2008,
Biotic – Sediment Interactions; an introduction
, Palaeogeography, Palaeoclimatology, Palaeoecology, Vol: 270, Pages: 217-219, ISSN: 0031-0182 -
Journal articleOsinski GR, Grieve RAF, Collins GS, et al., 2008,
The effect of target lithology on the products of impact melting
, METEORITICS & PLANETARY SCIENCE, Vol: 43, Pages: 1939-1954, ISSN: 1086-9379 -
Journal articleGorman GJ, Piggott MD, Wells MR, et al., 2008,
A systematic approach to unstructured mesh generation for ocean modelling using GMT and Terreno
, Computers & Geosciences, Vol: 34, Pages: 1721-1731, ISSN: 0098-3004A systematic approach to unstructured mesh generation for ocean modelling is presented. The method optimises unstructured meshes to approximate bathymetry to a user specified accuracy which may be defined as a function of longitude, latitude and bathymetry. GMT (Generic Mapping Tools) is used to perform the initial griding of the bathymetric data. Subsequently, the Terreno meshing package combines automated shoreline approximation, mesh gradation and optimisation methods to generate high-quality bathymetric meshes. The operation of Terreno is based upon clearly defined error measures and this facilitates the automation of unstructured mesh generation while minimising user intervention and the subjectivity that this can introduce.
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Journal articleBray VJ, Collins GS, Morgan JV, et al., 2008,
The effect of target properties on crater morphology: Comparison of central peak craters on the Moon and Ganymede.
, Meteoritics and Planetary Science, Vol: 43, Pages: 1979-1992 -
Journal articlePierazzo E, Artemieva N, Asphaug E, et al., 2008,
Validation of numerical codes for impact and explosion cratering: Impacts on strengthless and metal targets
, METEORITICS & PLANETARY SCIENCE, Vol: 43, Pages: 1917-1938, ISSN: 1086-9379 -
Journal articlePaul CRC, Allison PA, Brett CE, 2008,
The occurrence and preservation of ammonites in the Blue Lias Formation (Lower Jurassic) of Devon and Dorset, England and their palaeoecological, sedimentological and diagenetic significance
, Palaeogeography, Palaeoclimatology, Palaeoecology, Vol: 270, Pages: 258-272, ISSN: 0031-0182 -
Journal articleCollins GS, Kenkmann T, Osinski GR, et al., 2008,
Mid-sized complex crater formation in mixed crystalline-sedimentary targets: Insight from modeling and observation
, METEORITICS & PLANETARY SCIENCE, Vol: 43, Pages: 1955-1977, ISSN: 1086-9379 -
Journal articleLatham J-P, Munjiza A, Mindel J, et al., 2008,
Modelling of massive particulates for breakwater engineering using coupled FEMDEM and CFD
, PARTICUOLOGY, Vol: 6, Pages: 572-583, ISSN: 1674-2001- Author Web Link
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- Citations: 33
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Journal articleMorris G, Pursell MR, Neethling SJ, et al., 2008,
The effect of particle hydrophobicity, separation distance and packing patterns on the stability of a thin film
, JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 327, Pages: 138-144, ISSN: 0021-9797- Author Web Link
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- Citations: 33
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Journal articleSmith C, Neethling S, Cilliers JJ, 2008,
Air-rate profile optimisation: From simulation to bank improvement
, MINERALS ENGINEERING, Vol: 21, Pages: 973-981, ISSN: 0892-6875- Author Web Link
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- Citations: 12
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Journal articleNeethling SJ, Cilliers JJ, 2008,
Predicting air recovery in flotation cells
, MINERALS ENGINEERING, Vol: 21, Pages: 937-943, ISSN: 0892-6875- Author Web Link
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- Citations: 23
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Journal articleWells MR, Allison PA, Hampson GJ, et al., 2008,
Investigating tides in the Early Pennsylvanian Seaway of NW Eurasia using the Imperial College Ocean Model
, Geological Association of Canada Special Paper, Vol: 48, Pages: 363-387, ISSN: 0072-1042 -
SoftwareHam D, Farrell P, Gorman G, et al., 2008,
Spud
Spud is a generic system for defining, writing and processing options files for scientific computer models.The interfaces to scientific computer models are frequently primitive, under-documented and ad-hoc text files. This makes using and developing the model in question difficult and error-prone.With Spud, the model developer need only write a rules file (schema) which defines the options which the model takes and the relationship between them. The Spud component Diamond then provides an automatically generated graphical user interface which guides the user and validates the user's input against the schema. Diamond writes out an xml options file for use in Spud.The developer then uses libspud to read the options file into the model. Libspud can read any valid options file without further code modifications and makes the options available at any point in the model code at which they are required.Spud further provides the facility for the schema to be self-documenting and Diamond presents this documentation to the model user in a context-sensitive manner.
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Journal articleKramer SC, Stelling GS, 2008,
A conservative unstructured scheme for rapidly varied flows
, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Vol: 58, Pages: 183-212, ISSN: 0271-2091- Author Web Link
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- Citations: 42
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Journal articleMerton SR, Pain CC, Smedley-Stevenson RP, et al., 2008,
Optimal discontinuous finite element methods for the Boltzmann transport equation with arbitrary discretisation in angle
, ANNALS OF NUCLEAR ENERGY, Vol: 35, Pages: 1741-1759, ISSN: 0306-4549- Author Web Link
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- Citations: 8
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Conference paperPercival JR, Cotter CJ, Holm DD, 2008,
A Euler–Poincaré framework for the multilayer Green–Nagdhi equations
, Meeting held in Honor of Darryl D Holms on Geometry and Analysis in Physical Systems, Publisher: IOP Publishing, Pages: 344018-344031, ISSN: 1751-8113The Green–Nagdhi equations are frequently used as a model of the wave-like behaviour of the free surface of a fluid, or the interface between two homogeneous fluids of differing densities. Here we show that their multilayer extension arises naturally from a framework based on the Euler–Poincaré theory under an ansatz of columnar motion. The framework also extends to the travelling wave solutions of the equations. We present numerical solutions of the travelling wave problem in a number of flow regimes. We find that the free surface and multilayer waves can exhibit intriguing differences compared to the results of single layer or rigid lid models.
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Conference paperDavison TM, Collins GS, Ciesla FJ, 2008,
Numerical modelling of shock heating in porous planetesmial collisions
, 71st Annual Meeting of the Meteoritical-Society, Publisher: Meteoritical Society, Pages: A36-A36 -
Journal articleCollins GS, Morgan J, Barton P, et al., 2008,
Dynamic modeling suggests terrace zone asymmetry in the Chicxulub crater is caused by target heterogeneity
, EARTH PLANET SC LETT, Vol: 270, Pages: 221-230, ISSN: 0012-821X -
Journal articleBuchan AG, Pain CC, Eaton MD, et al., 2008,
Linear and quadratic hexahedral wavelets on the sphere for angular discretizations of the Boltzmann transport equation
, NUCLEAR SCIENCE AND ENGINEERING, Vol: 159, Pages: 127-152, ISSN: 0029-5639- Author Web Link
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- Citations: 8
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Journal articleBuchan AG, Pain CC, Eaton MD, et al., 2008,
Chebyshev spectral hexahedral wavelets on the sphere for angular discretisations of the Boltzmann transport equation
, ANNALS OF NUCLEAR ENERGY, Vol: 35, Pages: 1098-1108, ISSN: 0306-4549- Author Web Link
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- Citations: 5
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Journal articleWuennemann K, Collins GS, Osinski GR, 2008,
Numerical modelling of impact melt production in porous rocks
, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 269, Pages: 529-538, ISSN: 0012-821X- Author Web Link
- Cite
- Citations: 137
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Journal articleJackson MD, 2008,
Characterization of multiphase electrokinetic coupling using a bundle of capillary tubes model
, JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 113, ISSN: 2169-9313- Author Web Link
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- Citations: 56
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Journal articleCollins GS, Artemieva N, Wuennemann K, et al., 2008,
Evidence that Lake Cheko is not an impact crater
, TERRA NOVA, Vol: 20, Pages: 165-168, ISSN: 0954-4879- Author Web Link
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- Citations: 20
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Conference paperPiggott MD, Gorman GJ, Pain CC, et al., 2008,
A new computational framework for multi-scale ocean modelling based on adapting unstructured meshes
, 9th ICFD Conference on Numerical Methods for Fluid Dynamics, Pages: 1003-1015A new modelling framework is presented for application to a range of three-dimensional (3D) multi-scale oceanographic problems. The approach is based upon a finite element discretization on an unstructured tetrahedral mesh which is optimized to represent highly complex geometries. Throughout a simulation the mesh is dynamically adapted in 3D to optimize the representation of evolving solution structures. The adaptive algorithm makes use of anisotropic measures of solution complexity and a load-balanced parallel mesh optimization algorithm to vary resolution and allow long, thin elements to align with features such as boundary layers. The modelling framework presented is quite different from the majority of ocean models in use today, which are typically based on static-structured grids. Finite element (and volume) methods on unstructured meshes are, however, gaining popularity in the oceanographic community. The model presented here is novel in its use of unstructured meshes and anisotropic adaptivity in 3D, its ability to represent a range of coupled multi-scale solution structures and to simulate non-hydrostatic dynamics. Copyright (C) 2007 John Wiley & Sons, Ltd.
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Journal articlePiggott MD, Gorman GJ, Pain CC, et al., 2008,
A new computational framework for multi-scale ocean modelling based on adapting unstructured meshes
, International Journal for Numerical Methods in Fluids, Vol: 56, Pages: 1003-1015 -
Journal articleShaw B, Ambraseys NN, England PC, et al., 2008,
Eastern Mediterranean tectonics and tsunami hazard inferred from the AD 365 earthquake
, Nature Geoscience, Vol: 1, Pages: 268-276 -
Journal articleBuchan AG, Pain CC, Eaton MD, et al., 2008,
Self-adaptive spherical wavelets for angular discretizations of the Boltzmann transport equation
, NUCLEAR SCIENCE AND ENGINEERING, Vol: 158, Pages: 244-263, ISSN: 0029-5639A new method for applying anisotropic resolution in the angular domain of the Boltzmann transport equation is presented. The method builds on our previous work in which two spherical wavelet bases were developed for representing the direction of neutral particle travel. The method proposed here enables these wavelet bases to vary their angular approximations so that fine resolution may be applied only to the areas of the unit sphere (representing the direction of particle travel) that are important. We develop an error measure that operates in conjunction with the wavelet bases to determine this importance. A procedure by which the angular resolution is gradually refined for steady-state problems is also given.The adaptive wavelets are applied to three test problems that demonstrate the ability of the wavelets to resolve complex fluxes with relatively few functions, and to achieve this a particular emphasis is placed on their ability to approximate particle streaming through ducts with voids. It is shown that the wavelets are capable of applying the appropriate resolution (as dictated by the error measure) to the directional component of the angular flux at all spatial positions. This method therefore offers a new and highly efficient adaptive angular approximation method.
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Journal articleWarner M, Stekl I, Umpleby A, 2008,
Efficientand effective 3D wavefield tomography
, 70th European Association of Geoscientists and Engineers Conference and Exhibition 2008: Leveraging Technology. Incorporating SPE EUROPEC 2008, Vol: 3, Pages: 1607-1611We demonstrate 3D wavefield tomography applied to surface-streamer seismic data and obtain a result which appears to remove the distoring effects of shallow high-velocity channels.
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Journal articleWarner M, Stekl I, Umpleby A, 2008,
3D wavefield tomography: Synthetic and field data examples
, SEG Technical Program Expanded Abstracts, Vol: 27, Pages: 3330-3334, ISSN: 1052-3812Full wavefield tomography has become well established in two dimensions, but its extension into 3D for realistically sized problems is computationally daunting. In this paper, we present one of the first studies to apply 3D wavefield tomography to field data, and demonstrate that the method can solve useful exploration problems that that are not tractable by other methods.
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Journal articleJonoud S, Jackson MD, 2008,
New criteria for the validity of steady-state upscaling
, TRANSPORT IN POROUS MEDIA, Vol: 71, Pages: 53-73, ISSN: 0169-3913- Author Web Link
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- Citations: 22
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Journal articleC J Cotter, G Gorman, 2008,
Diagnostic tools for 3D unstructured oceanographic data
, Ocean Modelling, Vol: 20, Pages: 170-182 -
Journal articleCarmine L, Aristodemou E, Pain C, et al., 2008,
Inversion of time-dependent nuclear well-logging data using neural networks
, Geophysical Prospecting, Vol: 56, Pages: 115-140, ISSN: 0016-8025The purpose of this work was to investigate a new and fast inversion methodology for the prediction of subsurface formation properties such as porosity, salinity and oil saturation, using time-dependent nuclear well logging data. Although the ultimate aim is to apply the technique to real-field data, an initial investigation as described in this paper, was first required; this has been carried out using simulation results from the time-dependent radiation transport problem within a borehole. Simulated neutron and gamma-ray fluxes at two sodium iodide (NaI) detectors, one near and one far from a pulsed neutron source emitting at similar to 14 MeV, were used for the investigation. A total of 67 energy groups from the BUGLE96 cross section library together with 567 property combinations were employed for the original flux response generation, achieved by solving numerically the time-dependent Boltzmann radiation transport equation in its even parity form. Material property combinations (scenarios) and their correspondent teaching outputs (flux response at detectors) are used to train the Artificial Neural Networks (ANNs) and test data is used to assess the accuracy of the ANNs. The trained networks are then used to produce a surrogate model of the expensive, in terms of computational time and resources, forward model with which a simple inversion method is applied to calculate material properties from the time evolution of flux responses at the two detectors. The inversion technique uses a fast surrogate model comprising 8026 artificial neural networks, which consist of an input layer with three input units (neurons) for porosity, salinity and oil saturation; and two hidden layers and one output neuron representing the scalar photon or neutron flux prediction at the detector. This is the first time this technique has been applied to invert pulsed neutron logging tool information and the results produced are very promising. The next step in the procedure is to apply th
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Conference paperMunjiza A, Xiang J, Garcia X, et al., 2008,
The Virtual Geoscience Workbench, VGW: Open source tools for discontinuous systems
, Discrete Element Methods and Numerical Modelling of Discontinuum Mechanics, Pages: 113-121 -
Journal articleJonoud S, Jackson MD, 2008,
Validity of Steady-State Upscaling Techniques
, SPE Reservoir Evaluation and Engineering, Vol: April, Pages: 405-416 -
Conference paperSchiava D'Albano GG, Munjiza A, Rougier E, et al., 2008,
Fluid driven fracture processes in FEM/DEM analysis
, Discrete Element Methods and Numerical Modelling of Discontinuum Mechanics, DEM'08, Pages: 242-248 -
Conference paperJiang S, Pain CC, Carter JN, et al., 2008,
Nuclear Reactor Reactivity Prediction Using Feed Forward Artificial Neural Networks
, 5th International Symposium on Neural Networks, Publisher: SPRINGER-VERLAG BERLIN, Pages: 400-+, ISSN: 0302-9743 -
Conference paperGarcia X, Latham JP, Xiang J, et al., 2008,
Modelling of the forming processes of sandstones with irregular particles
, Discrete Element Methods and Numerical Modelling of Discontinuum Mechanics, DEM'08, Pages: 232-241 -
Conference paperXiang J, Latham JP, Munjiza A, et al., 2008,
Applications of the combined finite-discrete element method
, Discrete Element Methods and Numerical Modelling of Discontinuum Mechanics, Pages: 223-231 -
BookBosence DWJ, Allison PA, 2008,
Biotic sediment interactions: Selected papers from: Organism sediment relations and preservational windows; A tribute to the scientific career of Roland Goldring. Published in Palaeogeography, Palaeoclimatology, Palaeoecology
, Publisher: Elsevier Science Ltd. -
Conference paperLatham JP, Mindel J, Xiang J, et al., 2008,
Development of a modelling approach for large granular media used in coastal applications
, Discrete Element Methods and Numerical Modelling of Discontinuum Mechanics, Pages: 122-130 -
Journal articleRushmer T, Jackson MD, 2008,
Impact of melt segregation on tonalite–trondhjemite–granodiorite (TTG) petrogenesis
, Trans. Royal Society of Edinburgh: Earth Science, Vol: 79, Pages: 325-336 -
Journal articleAllison PA, Maeda H, TuZino T, et al., 2008,
Exceptional preservation within Pleistocene lacustrine sediments of Shiobara, Japan
, Palaois, Vol: 23, Pages: 260-266
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