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    Abolghasemi M, Piggott MD, Spinneken J, Vire A, Cotter CJ, Crammond Set al.,

    Simulating tidal turbines with mesh optimisation and RANS turbulence models

    , 2015 European Wave and Tidal Energy Conference
    Avdis A, Jacobs CT, Hill J, Piggott MD, Gorman GJet al.,

    Shoreline and Bathymetry Approximation in Mesh Generation for Tidal Renewable Simulations

    Due to the fractal nature of the domain geometry in geophysical flowsimulations, a completely accurate description of the domain in terms of acomputational mesh is frequently deemed infeasible. Shoreline and bathymetrysimplification methods are used to remove small scale details in the geometry,particularly in areas away from the region of interest. To that end, a novelmethod for shoreline and bathymetry simplification is presented. Existingshoreline simplification methods typically remove points if the resultantgeometry satisfies particular geometric criteria. Bathymetry is usuallysimplified using traditional filtering techniques, that remove unwanted Fouriermodes. Principal Component Analysis (PCA) has been used in other fields toisolate small-scale structures from larger scale coherent features in a robustway, underpinned by a rigorous but simple mathematical framework. Here wepresent a method based on principal component analysis aimed towardssimplification of shorelines and bathymetry. We present the algorithm in detailand show simplified shorelines and bathymetry in the wider region around theNorth Sea. Finally, the methods are used in the context of unstructured meshgeneration aimed at tidal resource assessment simulations in the coastalregions around the UK.

    Funke SW, Kramer SC, Piggott MD,

    Design optimisation and resource assessment for tidal-stream renewable energy farms using a new continuous turbine approach

    , Renewable Energy, ISSN: 1879-0682

    This paper presents a new approach for optimising the design of tidal stream turbine farms. In this approach, the turbine farm is represented by a turbine density function that specifies the number of turbines per unit area and an associated continuous locally-enhanced bottom friction field. The farm design question is formulated as a mathematical optimisation problem constrained by the shallow water equations and solved with efficient, gradient-based optimisation methods. The resulting method is accurate, computationally efficient, allows complex installation constraints, and supports different goal quantities such as to maximise power or profit. The outputs of the optimisation are the optimal number of turbines, their location within the farm, the overall farm profit, the farm's power extraction, and the installation cost.We demonstrate the capabilities of the method on a validated numerical model of the Pentland Firth, Scotland. We optimise the design of four tidal farms simultaneously, as well as individually, and study how farms in close proximity may impact upon one another.

    Mason PJ, Rosenbaum MS, Moore JM,

    Predicting future landslides using remotely sensed imagery: the Langhe Hills in Piemonte, NW Italy.

    , 8th International Symposium on Landslides

    Existing landslides in the Langhe Hills, NW Italy, have been identified using digital remotelysensed imagery on the basis of their textural and spectral characteristics. Landsat ThematicMapper and multi-temporal SPOT Panchromatic images reveal landslides produced by a stormevent which occurred in 1994, on the basis of key soil properties. High clay content in the soilsand weathered rock profile enhances moisture retention, particularly in hollows and on concaveslopes. Soil moisture assumes the role of a conditioning factor, alongside smectite and ironoxideswhich have been leached from the rocks, and facilitated by groundwater flow throughfractures. Digital images, produced from Landsat TM, representing hydrated mineral (clay), ironoxideand soil moisture content have enabled identification of areas where conditioning factorsare present.

    Nielsen SG, Yogodzinski G, Prytulak J, Plank T, Kay SM, Kay RW, Blusztajn J, Owens JD, Auro M, Kading Tet al.,

    Tracking along-arc sediment inputs to the Aluetian arc using thallium isotopes

    , Geochimica et Cosmochimica Acta, ISSN: 1872-9533
    Nielsen SG, Yogodzinski G, Prytulak J, Plank T, Kay SM, Kay RW, Blusztajn J, Owens JD, Auro M, Kading Tet al.,

    Tracking along-arc sediment inputs to the Aleutian arc using thallium isotopes

    , Geochimica et Cosmochimica Acta, ISSN: 1872-9533

    Sediment transport from the subducted slab to the mantle wedge is an importantprocess in understanding the chemical and physical conditions of arc magma generation. The Aleutian arc offers an excellent opportunity to study sediment transport processes because the subducted sediment flux varies systematically along strike (Kelemen et al., 2003) and many lavas exhibit unambiguous signatures of sediment addition to the sub-arc mantle (Morris et al.,1990). However, the exact sediment contribution to Aleutian lavas and how these sediments are transported from the slab to the surface are still debated. Thallium (Tl) isotope ratios have great potential to distinguish sediment fluxes in subduction zones because pelagic sediments and lowtemperaturealtered oceanic crust are highly enriched in Tl and display heavy and light Tl isotope compositions, respectively, compared with the upper mantle and continental crust. Here, we investigate the Tl isotope composition of lavas covering almost the entire Aleutianarc a well as sediments outboard of both the eastern (DSDP Sites 178 and 183) and central (ODP Hole 886C) portions of the arc. Sediment Tl isotope compositions change systematically from lighter in the Eastern to heavier in the Central Aleutians reflecting a larger proportion of pelagic sediments when distal from the North American continent. Lavas in the Eastern and CentralAleutians mirror this systematic change to heavier Tl isotope compositions to the west, which shows that the subducted sediment composition is directly translated to the arc east of Kanaga Island. Moreover, quantitative mixing models of Tl and Pb, Sr and Nd isotopes reveal that bulk sediment transfer of ~0.6-1.0% by weight in the Eastern Aleutians and ~0.2-0.6% by weight in the Central Aleutians can account for all four isotope systems. Bulk mixing models, however,require that fractionation of trace element ratios like Ce/Pb, Cs/Tl, and Sr/Nd in the Central and Eastern Aleutians occurs after the sediment c

    Nixon CW, McNeill LC, Bull JM, Bell RE, Gawthorpe RL, Henstock TJ, Christodoulou, Ford M, Taylor B, Sakellariou D, Ferentinos G, Papatheodorou G, Leeder M, Collier RELI, Goodliffe A, Sachpazi M, Kranis Het al.,

    Rapid spatio-temporal variations in rift structure during development of the Corinth Rift, central Greece

    , Tectonics, ISSN: 1944-9194
    Singh A, Gupta S, Sinha R, Carter A, Kristina KJ, Mark DF, Buylaert J-P, Mason PJ, Murray AS, Jain M, Paul Det al.,

    Large–scale avulsion of the late Quaternary Sutlej river in the NW Indo–Gangetic foreland basin

    , European Geosciences Union General Assembly 2015

    River avulsions are important processes in the spatial evolution of river systems in tectonically active sedimentary basins as they govern large–scale patterns of sediment routing. However, the pattern and timing of avulsions in large river systems are poorly documented and not well understood. Here we document late Quaternary paleo– river channel changes in the Indo–Gangetic basin of northwest India. Using a combination of satellite remote sensing and detailed sediment coring, we analyse the large–scale planform geometry, and detailed sedimentary andstratigraphic nature of a major fluvial sedimentary deposit in the shallow subsurface. This sediment body records aggradation of multiple fluvial channel fills. Satellite remote sensing analysis indicates the trace of the buried channel complex and demonstrates that it exists in region of the Himalayan foreland where no major rivers are currently present. Thus it records the former drainage pathway of a major river, which has since been diverted. We use optically stimulated luminescence dating techniques to develop an age model for the stratigraphic succession and hence constrain the timing of river channel existence and diversion. Provenance analysis based on U–Pb dating of detrital zircons and detrital mica Ar–Ar ages indicate sediment sources in the Higher Himalayan Crystalline andLesser Himalayan Crystalline Series indicating that this paleo–river channel system formed a major perennial river derived from the main body of the Himalaya. Specifically we are able to fingerprint bedrock sources in thecatchment of the present–day Sutlej river indicating that the paleo–fluvial system represents the former course of the Sutlej river prior to a major nodal avulsion to its present day course. Our results indicate that on geologically relatively short time–scales, we observe dramatic along strike shifts in the location of major Himalayan rivers. Our sediment records

    Skiada E, Kontoe S, Stafford P, Potts DMet al.,

    Canyon Depth Effect on Surface Ground Motion

    , 1st International Conference on Natural Hazards & Infrastructure

    Topographic effects are rarely accounted for in seismic design codes, despite their potential to significantly modify surfaceground motions. This paper investigates the influence of a canyon’s slope height on the surface ground motion through aparametric time-domain Finite Element (FE) study. A two-dimensional plane-strain model of an idealised canyon isconsidered for vertically propagating SV waves, using wavelets as input excitation. The model consists of two step-likeslopes with slope height (H), in a homogeneous linear elastic soil layer overlying rigid bedrock. The analysis results showthat the distribution of topographic aggravation at the ground surface varies significantly with normalized canyon depthover the input wavelength (H/λ) and it does not necessarily reach a maximum at a specific H/λ ratio, as has been suggestedin previous studies. The validity of this conclusion is investigated for different depths to bedrock and soil layer properties.

    Allen PA, Michael NA, D'Arcy M, Roda-Boluda DC, Whittaker AC, Duller RA, Armitage JJet al., 2017,

    Fractionation of grain size in terrestrial sediment routing systems

    , BASIN RESEARCH, Vol: 29, Pages: 180-202, ISSN: 0950-091X
    Collins GS, Lynch E, Mcadam R, Davison TMet al., 2017,

    A numerical assessment of simple airblast models of impact airbursts

    , Meteoritics and Planetary Science, ISSN: 1086-9379

    © 2017 The Meteoritical Society.Asteroids and comets 10-100 m in size that collide with Earth disrupt dramatically in the atmosphere with an explosive transfer of energy, caused by extreme air drag. Such airbursts produce a strong blastwave that radiates from the meteoroid's trajectory and can cause damage on the surface. An established technique for predicting airburst blastwave damage is to treat the airburst as a static source of energy and to extrapolate empirical results of nuclear explosion tests using an energy-based scaling approach. Here we compare this approach to two more complex models using the iSALE shock physics code. We consider a moving-source airburst model where the meteoroid's energy is partitioned as two-thirds internal energy and one-third kinetic energy at the burst altitude, and a model in which energy is deposited into the atmosphere along the meteoroid's trajectory based on the pancake model of meteoroid disruption. To justify use of the pancake model, we show that it provides a good fit to the inferred energy release of the 2013 Chelyabinsk fireball. Predicted overpressures from all three models are broadly consistent at radial distances from ground zero that exceed three times the burst height. At smaller radial distances, the moving-source model predicts overpressures two times greater than the static-source model, whereas the cylindrical line-source model based on the pancake model predicts overpressures two times lower than the static-source model. Given other uncertainties associated with airblast damage predictions, the static-source approach provides an adequate approximation of the azimuthally averaged airblast for probabilistic hazard assessment.

    D'Arcy M, Whittaker AC, Roda-Boluda DC, 2017,

    Measuring alluvial fan sensitivity to past climate changes using a self-similarity approach to grain-size fining, Death Valley, California

    , SEDIMENTOLOGY, Vol: 64, Pages: 388-424, ISSN: 0037-0746
    Elliott GM, Jackson CA-L, Gawthorpe RL, Wilson P, Sharp IR, Michelsen Let al., 2017,

    Late syn-rift evolution of the Vingleia Fault Complex, Halten Terrace, offshore Mid-Norway; a test of rift basin tectono-stratigraphic models

    , BASIN RESEARCH, Vol: 29, Pages: 465-487, ISSN: 0950-091X
    Lewis MM, Jackson CA-L, Gawthorpe RL, 2017,

    Tectono-sedimentary development of early syn-rift deposits: the Abura Graben, Suez Rift, Egypt

    , BASIN RESEARCH, Vol: 29, Pages: 327-351, ISSN: 0950-091X
    Ryan L, Magee C, Jackson CA-L, 2017,

    The kinematics of normal faults in the Ceduna Subbasin, offshore southern Australia: Implications for hydrocarbon trapping in a frontier basin

    , AAPG BULLETIN, Vol: 101, Pages: 321-341, ISSN: 0149-1423
    Schofield N, Holford S, Millett J, Brown D, Jolley D, Passey SR, Muirhead D, Grove C, Magee C, Murray J, Hole M, Jackson CA-L, Stevenson Cet al., 2017,

    Regional magma plumbing and emplacement mechanisms of the Faroe-Shetland Sill Complex: implications for magma transport and petroleum systems within sedimentary basins

    , BASIN RESEARCH, Vol: 29, Pages: 41-63, ISSN: 0950-091X
    Summersgill FC, Kontoe S, Potts DM, 2017,

    On the use of nonlocal regularisation in slope stability problems

    , COMPUTERS AND GEOTECHNICS, Vol: 82, Pages: 187-200, ISSN: 0266-352X
    Wrona T, Jackson CA-L, Huuse M, Taylor KGet al., 2017,

    Silica diagenesis in Cenozoic mudstones of the North Viking Graben: physical properties and basin modelling

    , BASIN RESEARCH, Vol: 29, Pages: 556-575, ISSN: 0950-091X
    Abolghasemi MA, Piggott MD, Spinneken J, Vire A, Cotter CJ, Crammond Set al., 2016,

    Simulating tidal turbines with multi-scale mesh optimisation techniques

    , JOURNAL OF FLUIDS AND STRUCTURES, Vol: 66, Pages: 69-90, ISSN: 0889-9746
    Adam A, Buchan AG, Piggott MD, Pain CC, Hill J, Goffin MAet al., 2016,

    Adaptive Haar wavelets for the angular discretisation of spectral wave models

    , JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 305, Pages: 521-538, ISSN: 0021-9991

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