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  • Conference paper
    Southern J, Gorman GJ, Piggott MD, Farrell PE, Bernabeu MO, Pitt-Francis Jet al., 2010,

    Anisotropic mesh adaptivity for cardiac electrophysiology

    , Pages: 929-938-929-938
  • Journal article
    Farrell PE, Piggott MD, Gorman GJ, Ham DA, Wilson CRet al., 2010,

    Automated continuous verification and validation for numerical simulation

    , Geoscientific Model Development Discussions, Vol: 3, Pages: 1587-1623
  • Journal article
    Pavlidis D, Gorman GJ, Gomes JLMA, Pain CC, ApSimon Het al., 2010,

    Synthetic-Eddy Method for Urban Atmospheric Flow Modelling

    , Boundary-Layer Meteorology, Vol: 136, Pages: 285-299
  • Conference paper
    Guo X, Gorman G, Ashworth M, Kramer S, Piggott M, Sunderland Set al., 2010,

    High Performance Computing Driven Software Development for Next-Generation Modelling of the Worlds Oceans

    , Cray Users Group Conference

    The Imperial College Ocean Model (ICOM) is an open-source next generation ocean model build upon finite element methods and anisotropic unstructured adaptive meshing. Since 2009, a project has been funded by EPSRC to optimise the ICOM for the UK national high-end computing resource, HECToR (Cray XT4). Extensive use of profiling tools such as CrayPAT and Vampir, has been made in order to understand performance issues of the code on the Cray XT4. Of particular interest is the scalability of the sparse linear solvers and the algebraic multigrid preconditioners required to solve the system of equations.

  • Journal article
    Miles BE, Pain CC, Gomes JLMA, Tollit Bet al., 2010,

    Simulation of a gas-cooled fluidized bed nuclear reactor. Part I: Mixed oxide fuels

    , Annals of Nuclear Energy, Vol: 37, Pages: 999-1013
  • Journal article
    Aristodemou E, Bentham T, Pain C, Colvile R, Robins A, ApSimon Het al., 2009,

    A comparison of mesh-adaptive LES with wind tunnel data for flow past buildings: Mean flows and velocity fluctuations

    , ATMOSPHERIC ENVIRONMENT, Vol: 43, Pages: 6238-6253, ISSN: 1352-2310
  • Journal article
    Piggott MD, Farrell PE, Wilson CR, Gorman GJ, Pain CCet al., 2009,

    Anisotropic mesh adaptivity for multi-scale ocean modelling

    , PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 367, Pages: 4591-4611, ISSN: 1364-503X
  • Journal article
    Bland PA, Jackson MD, Coker RF, Cohen BA, Webber JBW, Lee MR, Duffy CM, Chater RJ, Ardakani MG, McPhail DS, McComb DW, Benedix GKet al., 2009,

    Why aqueous alteration in asteroids was isochemical: High porosity not equal high permeability

    , EARTH AND PLANETARY SCIENCE LETTERS, Vol: 287, Pages: 559-568, ISSN: 0012-821X
  • Journal article
    Fang F, Pain CC, Navon IM, Gorman GJ, Piggott MD, Allison PA, Goddard AJHet al., 2009,

    A POD goal-oriented error measure for mesh optimization

    , International Journal for Numerical Methods in Fluids, Vol: 63, Pages: 185-206, ISSN: 1097-0363

    The approach for designing an error measure to guide an adaptive meshing algorithm proposed in Power et al. (Ocean Modell. 2006; 15:3-38) is extended to use a POD adjoint-based method, thus facilitating efficient primal and adjoint integration in time. The aim is to obtain a new mesh that can adequately resolve all the fields at all time levels, with optimal (w.r.t. the functional) efficiency. The goal-based method solves both the primal and adjoint equations to form the overall error norms, in the form of a metric tensor. The tetrahedral elements are then optimized so that they have unit size in Riemannian space defined with respect to the metric tensor.This is the first attempt to use POD to estimate an anisotropic error measure. The metric tensor field can be used to direct anisotropic mesh adaptivity. The resulting mesh is optimized to efficiently represent the solution fields over a given time period. The calculation of the error measures is carried out in the reduced space. The POD approach facilitates efficient integration backwards in time and yields the sensitivity analysis necessary for the goal-based error estimates. The accuracy of both the primal and adjoint-reduced models is thus optimized (through the use of anisotropic mesh adaptivity). In addition, the functional for optimizing meshes has been designed to be consistent with that for 4D Var data assimilation.

  • Journal article
    Avdis A, Lardeau S, Leschziner M, 2009,

    Large Eddy Simulation of Separated Flow over a Two-dimensional Hump with and without Control by Means of a Synthetic Slot-jet

    , FLOW TURBULENCE AND COMBUSTION, Vol: 83, Pages: 343-370, ISSN: 1386-6184
  • Journal article
    Neethling SJ, Cilliers JJ, 2009,

    The entrainment factor in froth flotation: Model for particle size and other operating parameter effects

    , INTERNATIONAL JOURNAL OF MINERAL PROCESSING, Vol: 93, Pages: 141-148, ISSN: 0301-7516
  • Journal article
    Getsinger A, Rushmer T, Jackson MD, Baker Det al., 2009,

    Generating High Mg-numbers and Chemical Diversity in Tonalite-Trondhjemite-Granodiorite (TTG) Magmas during Melting and Melt Segregation in the Continental Crust

    , JOURNAL OF PETROLOGY, Vol: 50, Pages: 1935-1954, ISSN: 0022-3530
  • Conference paper
    Latham J-P, Xiang J,

    Application of the finite-discrete element method to dynamic stress development in armour units and armour layers

    , Coasts, Marine Structures and Breakwaters 2009, Adapting to Change
  • Journal article
    Jackson MD, Hampson GJ, Sech RP, 2009,

    Three-dimensional modeling of a shoreface-shelf parasequence reservoir analog: Part 2. Geologic controls on fluid flow and hydrocarbon recovery

    , AAPG BULLETIN, Vol: 93, Pages: 1183-1208, ISSN: 0149-1423
  • Journal article
    Sech RP, Jackson MD, Hampson GJ, 2009,

    Three-dimensional modeling of a shoreface-shelf parasequence reservoir analog: Part 1. Surface-based modeling to capture high-resolution facies architecture

    , AAPG Bulletin, Vol: 93, Pages: 1155-1181, ISSN: 0149-1423
  • Journal article
    Hopcroft PO, Gallagher K, Pain CC, 2009,

    A Bayesian partition modelling approach to resolve spatial variability in climate records from borehole temperature inversion

    , GEOPHYSICAL JOURNAL INTERNATIONAL, Vol: 178, Pages: 651-666, ISSN: 0956-540X
  • Journal article
    Hopcroft PO, Gallagher K, Pain CC, Fang Fet al., 2009,

    Three-dimensional simulation and inversion of borehole temperatures for reconstructing past climate in complex settings

    , JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE, Vol: 114, ISSN: 0148-0227

    An understanding of the way that ground surface temperatures have changed with time contributes to our knowledge of past climate change. One approach that has been used to achieve this is to relate deviations in borehole temperature depth profiles to past ground surface temperatures. This paper describes a new computationally efficient reduced order approach that eliminates problems associated with very localised borehole terrain affects. This approach expands upon a world-leading expertise in reduced order modelling methods and facilitates the use of a much broader range of geothermal data to be used for palaeoclimate reconstruction purposes.

  • Conference paper
    Merton SR, Pain CC, Smedley-Stevenson RP, Buchan AG, Eaton MDet al., 2009,

    A non-linear optimal discontinuous Petrov-Galerkin method for stabilising the solution of the transport equation

    , International Conference on Mathematics, Computational Methods & Reactor Physics
  • Journal article
    Wang Y, Neethling SJ, 2009,

    The relationship between the surface and internal structure of dry foam

    , COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol: 339, Pages: 73-81, ISSN: 0927-7757
  • Journal article
    Fang F, Pain CC, Navon IM, Piggott MD, Gorman GJ, Allison PA, Goddard AJHet al., 2009,

    Reduced-order modelling of an adaptive mesh ocean model

    , INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Vol: 59, Pages: 827-851
  • Journal article
    Ham DA, Farrell PE, Gorman GJ, Maddison JR, Wilson CR, Kramer SC, Shipton J, Collins GS, Cotter CJ, Piggott MDet al., 2009,

    Spud 1.0: generalising and automating the user interfaces of scientific computer models

    , Geoscientific Model Development, Vol: 2, Pages: 33-42

    The interfaces by which users specify the scenarios to be simulated by scientific computer models are frequently primitive, under-documented and ad-hoc text files which make using the model in question difficult and error-prone and significantly increase the development cost of the model. In this paper, we present a model-independent system, Spud, which formalises the specification of model input formats in terms of formal grammars. This is combined with an automated graphical user interface which guides users to create valid model inputs based on the grammar provided, and a generic options reading module, libspud, which minimises the development cost of adding model options. Together, this provides a user friendly, well documented, self validating user interface which is applicable to a wide range of scientific models and which minimises the developer input required to maintain and extend the model interface.

  • Journal article
    Latham JP, Mindel J, Xiang J, Guises R, Garcia X, Pain C, Gorman G, Piggott M, Munjiza Aet al., 2009,

    Coupled FEMDEM/Fluids for coastal engineers with special reference to armour stability and breakage

    , Geomechanics and Geoengineering, Vol: 4, Pages: 39-53, ISSN: 1748-6033
  • Journal article
    Agung A, Lathouwers D, van der Hagen THJJ, van Dam H, Pain CCet al., 2009,

    ON AN IMPROVED DESIGN OF A FLUIDIZED BED NUCLEAR REACTOR-II: LINEAR STABILITY AND TRANSIENT ANALYSIS

    , NUCLEAR TECHNOLOGY, Vol: 165, Pages: 133-144, ISSN: 0029-5450
  • Journal article
    Ham DA, Farrell PE, Gorman GJ, Maddison JR, Wilson CR, Kramer SC, Shipton J, Collins GS, Cotter CJ, Piggott MDet al., 2009,

    Spud 1.0: generalising and automating the user interfaces of scientific computer models

    , GEOSCIENTIFIC MODEL DEVELOPMENT, Vol: 2, Pages: 33-42, ISSN: 1991-959X
  • Conference paper
    Latham JP, Xiang J, 2009,

    Application of the finite-dicrete element method to dynamic stress development in armour units and armour layers

    , Coasts, Marine Structures and Breakwaters 2009, Publisher: Thomas Telford
  • Journal article
    Jaafar MZ, Vinogradov J, Jackson MD, 2009,

    Measurements of Streaming Potential Coupling Coefficient in Sandstones Saturated with High Salinity NaCl Brine

    , Geophysical Research Letters
  • Journal article
    Halgedahl SL, Jarrard RD, Brett CE, Allison PAet al., 2009,

    Geophysical and geological signatures of relative sea level change in the upper Wheeler Formation, Drum Mountains, West-Central Utah: A perspective into exceptional preservation of fossils

    , Palaeogeography, Palaeoclimatology, Palaeoecology, Vol: 277, Pages: 34-56, ISSN: 0031-0182
  • Journal article
    Jaafar MZ, Vinogradov J, Jackson MD, Saunders JH, Pain CCet al., 2009,

    Measurements of streaming potential for downhole monitoring in intelligent wells

    , SPE, Vol: 120460
  • Conference paper
    Gorman GJ, Pain CC, Piggott MD, Umpleby AP, Farrell PE, Maddison JRet al., 2009,

    Interleaved parallel tetrahedral mesh optimisation and dynamic load-balancing

    , Brussels, Belgium, the fourth International Conference on Adaptive Modeling and Simulation
  • Journal article
    Pain CC, Gomes JLMA, Eaton MD, Goddard AJH, Tollit B, Hadi Jet al., 2009,

    Modelling of Granular Materials in the FETCH Coupled Criticality Code

    , Transactions of the American Nuclear Society, Vol: 100, Pages: 331-334, ISSN: 0003-018X
  • Journal article
    Garcia X, Lateef A, Blunt M, Matthai S, Latham JPet al., 2009,

    Numerical study of the effects of particle shape and polydispersity on permeability

    , Physics Review E, Vol: 80

    We study through numerical simulations the dependence of the hydraulic permeability of granular materials on the particle shape and the grain size distribution. Several models of sand are constructed by simulating the settling under gravity of the grains; the friction coefficient is varied to construct packs of different porosity. The size distribution and shapes of the grains mimic real sands. Fluid flow is simulated in the resulting packs using a finite element method and the permeability of the packs is successfully compared with available experimental data. Packs of nonspherical particles are less permeable than sphere packs of the same porosity. Our results indicate that the details of grain shape and size distribution have only a small effect on the permeabilty of the systems studied.

  • Conference paper
    Xiang J, Mindel J, Latham JP, Pain C, Piggott M, Guises R, Garcia X, Munjiza Aet al., 2009,

    A combined FEM and DEM Fluids-Particulates model of waves interacting with granular media

    , Fifth International Conference on Coastal Structures, Publisher: World Scientific Publishing Co. Pte. Ltd, Pages: 1441-1452
  • Journal article
    Christeson GL, Collins GS, Morgan JV, Gulick SPS, Barton PJ, Warner MRet al., 2009,

    Mantle deformation beneath the Chicxulub impact crater

    , Earth and Planetary Science Letters, Vol: 284, Pages: 249-257, ISSN: 0012-821X
  • Journal article
    Farrell PE, Piggott MD, Pain CC, Gorman GJ, Wilson CRet al., 2009,

    Conservative interpolation between unstructured meshes via supermesh construction

    , Computer Methods in Applied Mechanics and Engineering, Vol: 198, Pages: 2632-2642
  • Journal article
    Xiang J, Munjiza A, Latham J-P, 2009,

    Finite strain, finite rotation quadratic tetrahedral element for the combined finite-discrete element method

    , International Journal for Numerical Methods in Engineering, Vol: 79, Pages: 946-978

    In the past, the combined finite-discrete element was mostly based on linear tetrahedral finite elements. Locking problems associated with this element can seriously degrade the accuracy of their simulations. In this work an efficient ten-noded quadratic element is developed in a format suitable for the combined finite-discrete element method (FEMDEM). The so-called F-bar approach is used to relax volumetric locking and an explicit finite element analysis is employed. A thorough validation of the numerical method is presented including five static and four dynamic examples with different loading, boundary conditions, and materials. The advantages of the new higher-order tetrahedral element are illustrated when brought together with contact detection and contact interaction capability within a new fully 3D FEMDEM formulation. An application comparing stresses generated within two drop experiments involving different unit specimens called Vcross and VRcross is shown. The Vcross and VRcross units of 3.5 × 104kg show very different stress generation implying different survivability upon collision with a deformable floor. The test case shows the FEMDEM method has the capability to tackle the dynamics of complex-shaped geometries and massive multi-body granular systems typical of concrete armour and rock armour layers.

  • Journal article
    Ham DA, Pain CC, Hanert E, Pietrzak J, Schröter Jet al., 2009,

    Special Issue: The sixth international workshop on unstructured mesh numerical modelling of coastal, shelf and ocean flows. Imperial College London, September 19-21, 2007

    , Ocean Modelling, Vol: 28, ISSN: 1463-5003
  • Journal article
    Cotter CJ, Ham DA, Pain CC, 2009,

    A mixed discontinuous/continuous finite element pair for shallow-water ocean modelling

    , Ocean Modelling, Vol: 26, Pages: 86-90, ISSN: 1463-5003

    We introduce a mixed discontinuous/continuous finite element pair for ocean modelling, with continuous quadratic layer thickness and discontinuous velocity. We investigate the finite element pair applied to the linear shallow-water equations on an f-plane. The element pair has the property that all geostrophically balanced states which strongly satisfy the boundary conditions have discrete divergence equal to exactly zero and hence are exactly steady states of the discretised equations. This means that the finite element pair has excellent geostrophic balance properties. We also show that the element pair applied to the non-rotating linear shallow-water equations does not have any spurious small eigenvalues. We illustrate these properties using numerical tests and provide convergence calculations which show that the numerical solutions have errors which decay quadratically with element edge length for both velocity and layer thickness.

  • Journal article
    Fang F, Pain CC, Navon IM, Piggott MD, Gorman GJ, Farrell PE, Allison PA, Goddard AJHet al., 2009,

    A POD reduced-order 4D-Var adaptive mesh ocean modelling approach

    , Int. J. Numer. Meth. Fluids, Vol: 60, Pages: 709-732

    This paper presents a novel approach for inverting a complex ocean model via a proper orthogonal decomposition. The inversion is achieved through the construction of an adjoint model and used to assimilate data in a similar manner to that used in weather forecasting. This is an incredibly important capability for an ocean model, however it is both complex to construct and also can be computationally expensive. The approach proposed here addresses both of these important issues by constructing an efficient and easy to compute adjoint directly from the reduced order model. The approach is demonstrated by inverting for initial conditions in an ocean gyre simulation. The methodology proposed here led directly to the award of a £1M EPSRC grant (EP/I00405X) to develop reduced order and adjoint models for coastal oceanography. Cited 11 times.

  • Conference paper
    Mindel J, Collins G, Latham JP, Pain C, Munjiza Aet al., 2009,

    Towards a numerical wave simulator using the two-fluid interface tracking approach combined with a novel ALE scheme

    , Fifth International Conference on Coastal Structures, Publisher: World Scientific Publishing Co. Pte, Pages: 1465-1476
  • Journal article
    Brett CE, Allison PA, DeSantis MK, Liddell WD, Kramer Aet al., 2009,

    Sequence stratigraphy, cyclic facies, and lagerstatten in the Middle Cambrian Wheeler and Marjum Formations, Great Basin, Utah

    , Palaeogeography, Palaeoclimatology, Palaeoecology, Vol: 277, Pages: 9-33, ISSN: 0031-0182
  • Journal article
    Fang F, Pain CC, Navon IM, Gorman GJ, Piggott MD, Allison PA, Farrell P, Goddard AJHet al., 2009,

    A POD reduced order unstructured mesh ocean modelling method for moderate Reynolds number flows

    , Ocean Modelling, Vol: 28, Pages: 127-136, ISSN: 1463-5003
  • Journal article
    Garcia X, Latham J-P, Xiang J, Harrison JPet al., 2009,

    A clustered overlapping sphere algorithm to represent real particles in discrete element modelling

    , Geotechnique
  • Journal article
    Guises R, Xiang J, Munjiza A, Latham J-Pet al., 2009,

    Granular packing: Numerical Simulation and Characterization of the Effect of Particle Shape

    , Granular Matter, Vol: 11, Pages: 281-292

    The packing of granular particles is investigated using a combined finite-discrete element approach. One of the aims of this paper is to present an application of a recently improved numerical simulation technique for deformable granular material with arbitrary shapes. Our study is focused on the influence of the effect of the particle shape on (1) the emergent properties of a granular pack (packing density,coordination number, force distribution), and on (2) the spatial distribution of the stress.Aset of simulations that mimick the sedimentation process is carried out, with varying input parameters, such as contact friction and particle shape. It is shown that the eccentricity of the particles not only significantly influences the final density of the pack but also the distribution of the stress and the contact forces. The presence of surface friction increases the amount of disorder within the granular system. Stress heterogeneities and force chain patterns propagate through the particles more efficiently than for the frictionless systems. The results also suggest that for the monodisperse systems investigated the coordination number is one of the factors that controls the distribution of the stress within a granular medium.

  • Conference paper
    Latham JP, Mindel J, Guises R, Garcia X, Xiang J, Pain C, Munjiza Aet al., 2009,

    Coupled FEM-DEM and CFD for coastal structures: application to armour stability and breakage

    , Proceedings of the Fifth International Conference on Coastal Structures, Publisher: World Scientific Publishing Co. Pte. Ltd, Pages: 1453-1464
  • Journal article
    Xiang J, McGlinchey D, Latham J-P, 2009,

    An investigation of segregation and mixing in dense phase pneumatic conveying

    , Granular Matter
  • Journal article
    Cotter CJ, Ham DA, Pain CC, Reich Set al., 2009,

    LBB stability of a mixed Galerkin finite element pair for fluid flow simulations

    , Journal of Computational Physics, Vol: 228, Pages: 336-348

    We 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.

  • Journal article
    Xiang J, Munjiza A, Latham JP, Guises R, Xiang J, Munjiza A, Latham J-P, Guises Ret 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 article
    Latham J-P, Mindel JE, Xiang J, Guises R, Garcia X, Pain CC, Gorman G, Piggott M, Munjiza A, Latham J-P, Mindel JE, Xiang J, Guises R, Garcia X, Pain CC, Gorman G, Piggott M, Munjiza Aet 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 article
    Fang F, Pain CC, Navon IM, Piggott MD, Gorman GJ, Allison PA, Goddard AJHet 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 article
    Munjiza A, Xiang J, Garcia X, Latham JP, Schiava DAlbano GG, John NWMet al., 2009,

    The Virtual Geoscience Workbench, VGW: Open Source tools for discontinuous systems

    , Particuology, Vol: in press

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