Title: Experimental and numerical investigations of a two-body floating-point absorber wave energy converter in regular waves

Abstract

This paper presents experimental and numerical studies on the hydrodynamics of a two-body floating-point absorber (FPA) wave energy converter (WEC) under both extreme and operational wave conditions. In this study, the responses of the WEC in heave, surge, and pitch were evaluated for various regular wave conditions. For extreme condition analysis, we assume the FPA system has a survival mode that locks the power-take-off (PTO) mechanism in extreme waves, and the WEC moves as a single body in this scenario. A series of Reynolds-averaged Navier-Stokes (RANS) simulations was performed for the survival condition analysis, and the results were validated with the measurements from experimental wave tank tests. For the FPA system in operational conditions, both a boundary element method (BEM) and the RANS simulations were used to analyze the motion response and power absorption performance. Additional viscous damping, primarily induced by flow separation and vortex shedding, is included in the BEM simulation as a quadratic drag force proportional to the square of body velocity. The inclusion of viscous drag improves the accuracy of BEM's prediction of the heave response and the power absorption performance of the FPA system, which agrees well with experimental data and the RANS simulation results overmore » a broad range of incident wave periods, except near resonance in large wave height scenarios. Overall, the experimental and numerical results suggest that nonlinear effects, caused by viscous damping and interaction between waves and the FPA, significantly influence the system response and power absorption performance. Nonlinear effects were found to be particularly significant when the wave height was large and the period was near or shorter than the resonant period of the FPA system. The study is expected to be helpful for understanding the nonlinear interaction between waves and the FPA system so that the structure of the FPA can be adequately designed.« less

Authors:

Xu, Qianlong ^[1]; Li, Ye ^[1]; Yu, Yi-Hsiang  ^[2];

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Ding, Boyin ^[3]; Jiang, Zhiyu ^[4]; Lin, Zhiliang ^[1]; Cazzolato, Benjamin ^[3]

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+ Show Author Affiliations

1. Shanghai Jiao Tong Univ. (China)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
3. Univ. of Adelaide, SA (Australia)
4. Univ. of Agder, Grimstad (Norway)

Publication Date:

Thu Sep 05 00:00:00 EDT 2019

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE-4W)

OSTI Identifier:

1567026

Alternate Identifier(s):

OSTI ID: 1693616

Report Number(s):

NREL/JA-5000-73581
Journal ID: ISSN 0889-9746

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Fluids and Structures

Additional Journal Information:

Journal Volume: 91; Journal ID: ISSN 0889-9746

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

16 TIDAL AND WAVE POWER; wave energy; floating-point absorber; experimental test; Reynolds-averaged Navier-Stokes equations; boundary element method; viscous damping; nonlinear effect