2,737,666 research outputs found

    A Three-dimensional Numerical Model for Baroclinic Dynamic in the Malacca Strait

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    The circulation in the Malacca Strait is simulated using a three-dimensionalbaroclinic numerical model. The circulation model isderived from the combined effects of tides, wind, meteorologicalforcings, temperature and salinity. The computational results producedpattern of general circulation and also sea surface temperature andsalinity. In the present study, the pattem of current circulation in theMalacca Strait coincided with the work [7]

    Numerical modelling of wave penetration in Ostend Harbour

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    The initial Ostend harbour entrance at the North Sea coast of Belgium is being modified and extended with two new rubble-mound breakwaters. Through an integrated study of the wave penetration in Ostend harbour, the waves are being acquired by prototype measurements and physical and numerical modelling is carried out. Two numerical models are used. SimWave is a numerical model based on Nwogu’s extended Boussinesq equations. The second numerical model is MILDwave, a mild-slope wave propagation model based on the equations of Radder and Dingemans. The present study concentrates on applications of the numerical models, throughout the different design stages and construction phases of the new breakwaters

    A Model for Understanding Numerical Stability

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    We present a model of roundoff error analysis that combines simplicity with predictive power. Though not considering all sources of roundoff within an algorithm, the model is related to a recursive roundoff error analysis and therefore capable of correctly predicting stability or instability of an algorithm. By means of nontrivial examples, such as the componentwise backward stability analysis of Gaussian elimination with a single iterative refinement step, we demonstrate that the model even yields quantitative backward error bounds that show all the known problem-dependent terms (with the exception of dimension-dependent constants, which are the weak spot of any a priori analysis). The model can serve as a convenient tool for teaching or as a heuristic device to discover stability results before entering a further, detailed analysis

    A numerical model of the VKS experiment

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    We present numerical simulations of the magnetic field generated by the flow of liquid sodium driven by two counter-rotating impellers (VKS experiment). Using a dynamo kinematic code in cylindrical geometry, it is shown that different magnetic modes can be generated depending on the flow configuration. While the time averaged axisymmetric mean flow generates an equatorial dipole, our simulations show that an axial field of either dipolar or quadrupolar symmetry can be generated by taking into account non-axisymmetric components of the flow. Moreover, we show that by breaking a symmetry of the flow, the magnetic field becomes oscillatory. This leads to reversals of the axial dipole polarity, involving a competition with the quadrupolar component.Comment: 6 pages, 5 figure

    An analytical model for the influence of contact resistance on thermoelectric efficiency

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    An analytical model is presented that can account for both electrical and hot and cold thermal contact resistances when calculating the efficiency of a thermoelectric generator. The model is compared to a numerical model of a thermoelectric leg, for 16 different thermoelectric materials, as well as the analytical models of Ebling et. al. (2010) and Min \& Rowe (1992). The model presented here is shown to accurately calculate the efficiency for all systems and all contact resistances considered, with an average difference in efficiency between the numerical model and the analytical model of 0.07±0.35-0.07\pm0.35 pp. This makes the model more accurate than previously published models. The maximum absolute difference in efficiency between the analytical model and the numerical model is 1.14 pp for all materials and all contact resistances considered.Comment: 8 pages, 5 figure
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