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    Influence of nonlinear Froude–Krylov forces on the performance of two wave energy points absorbers


    Penalba, Markel and Mérigaud, Alexis and Gilloteaux, Jean-Christophe and Ringwood, John (2017) Influence of nonlinear Froude–Krylov forces on the performance of two wave energy points absorbers. Journal of Ocean Engineering and Marine Energy, 3 (3). pp. 209-220. ISSN 2198-6444

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    Abstract

    Nonlinear behaviour of wave energy converters in power production mode can be relevant depending on the sea-state, the geometry or the motion of the device. Therefore, mathematical models used to simulate the behaviour of the device may need to include nonlinear effects. This paper studies the impact of modelling nonlinear Froude–Krylov forces by computing the pressure over the instantaneous wetted surface and uses a nonlinear wave theory (the Rienecker–Fenton’s theory) including nonlinear free-surface boundary conditions, to be more consistent with the computation of nonlinear Froude–Krylov forces. First, geometric nonlinearities are studied through the consideration of two heaving point absorbers with different geometrical characteristics: a truncated cylinder with a constant cross-sectional area (CSA) and a sphere with a non-uniform CSA. Then, nonlinearities related to the body dynamics are studied by applying a latching control strategy, which highlights the effect of nonlinear dynamics, showing the necessity to consider nonlinear WEC models as a basis for model-based control design. Results show that the performance of a standard fixed-time latching strategy drops considerably when applying nonlinear dynamics, so the fixed-time latching strategy is modified implementing the adaptive latching strategy. The impact of nonlinear Froude–Krylov forces is demonstrated to be low for devices with a constant CSA, but significant for devices of varying CSA.

    Item Type: Article
    Keywords: Wave energy; Nonlinear incident waves; Nonlinear Froude–Krylov forces; Adaptive latching control;
    Academic Unit: Faculty of Science and Engineering > Electronic Engineering
    Faculty of Science and Engineering > Research Institutes > Centre for Ocean Energy Research
    Item ID: 11775
    Identification Number: https://doi.org/10.1007/s40722-017-0082-x
    Depositing User: Professor John Ringwood
    Date Deposited: 20 Nov 2019 17:34
    Journal or Publication Title: Journal of Ocean Engineering and Marine Energy
    Publisher: Springer
    Refereed: Yes
    URI:

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