5 research outputs found

    A new family of real-time redictor-corrector integration algorithms

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    This paper describes a variation of the conventional two-pass explicit Adams- Moulton predictor-corrector integration methods which is suitable for real-time simulation. In this new method the first pass through the state equations uses an Adams-Bash forth type of predictor algo rithm to campute an estimate of the state at the n+1/2 frame instead of the n+1 frame, as is customary. This estimate is then used to compute the derivative at the n+1/2 frame which, along with derivatives at the n, n-1, n-2, ... frames is used in the final corrector pass to calculate the state at the n+1 frame. Unlike conventional two-pass Adams- Moulton methods, these new versions are compatible with real-time inputs. The paper shows that they are also superior based on dynamic accuracy measures and stability measures. A three-pass predictor-corrector integration algorithm compatible with real- time inputs is also presented and shown to yield significantly more accurate results than 3rd-order RK (Runge-Kutta) integra tion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68531/2/10.1177_003754979105700308.pd

    Efficient recursive Adams–Bashforth methods in molecular dynamics simulations of N-body systems interacting through pairwise potentials

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    A recursive multistep Adams–Bashforth method applied to the Molecular Dynamics simulations of N-body systems interacting through pairwise force fields is introduced and analysed. Equations of motion are obtained using a set of Cartesian coordinates solved by means of an Adams–Bashforth numerical integration scheme of order s, which requires the iterative computation of function time derivatives. The proposed algorithm has been implemented using a programming approach that makes it possible to re-use a source code resulting in small codes, easy to maintain. Practical examples and benchmarks that illustrate the performance of these implementations are included. The study of its performance gives clues to evaluate its efficiency and precision. Numerical tests for a N-particle system are made on the equilibrium configuration of liquid argon near its triple point at 86.5 K and 0.021 1/Å^3. In most cases, the algorithms here presented outperform those implemented traditionally as the Gear corrector-predictor or the Verlet family, leading to important savings in terms of total computation times and significantly increasing the numerical precision obtained with standard algorithms.Postprint (author's final draft

    Research in computerized structural analysis and synthesis

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    Computer applications in dynamic structural analysis and structural design modeling are discussed

    ICASE/LaRC Workshop on Benchmark Problems in Computational Aeroacoustics (CAA)

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    The proceedings of the Benchmark Problems in Computational Aeroacoustics Workshop held at NASA Langley Research Center are the subject of this report. The purpose of the Workshop was to assess the utility of a number of numerical schemes in the context of the unusual requirements of aeroacoustical calculations. The schemes were assessed from the viewpoint of dispersion and dissipation -- issues important to long time integration and long distance propagation in aeroacoustics. Also investigated were the effect of implementation of different boundary conditions. The Workshop included a forum in which practical engineering problems related to computational aeroacoustics were discussed. This discussion took the form of a dialogue between an industrial panel and the workshop participants and was an effort to suggest the direction of evolution of this field in the context of current engineering needs
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