| 研究課題/領域番号 |
18K13939
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| 研究機関 | 九州大学 |
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研究代表者 |
劉 盈溢 九州大学, 応用力学研究所, 助教 (30799127)
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| 研究期間 (年度) |
2018-04-01 – 2021-03-31
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| キーワード | wave energy converter / large arrays / multi-body hydrodynamics / parallel computation |
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| 研究実績の概要 |
Wave energy, as one of the main sources of ocean renewable energies, is prospective to release the pain of energy shortage in the near future. Wave energy converters (WECs), are normally designed to be deployed in large arrays among which every single device interacts with all the others through diffracting and radiating waves and absorbing powers. The present project aims to establish a sophisticated isogeometric boundary element method (IGA-BEM) for evaluating the multi-body hydrodynamics precisely. Some important advancements have been achieved last year. An efficient algorithm combining various series expansions for fast evaluation of free-surface Green's function has been consummated, followed by releasing an open-source code FinGreen3D on GitHub after massive tests and validations. Up to two planes of symmetry have been modeled to speed up the computation. Both of the lower-upper (LU) decomposition method and the generalized minimal residual method (GMRES) have been adopted to solve the resultant algebraic system of wave potentials quickly instead of the existing direct Gaussian elimination method. Multi-body hydrodynamic interactions have been further modeled as an extension of the single body solver. Parallelization of the computation code has been successfully implemented with the aid of the OpenMP technique. Moreover, the IGA concept utilizing the T-spline technology is smoothly under development and an alternative Enhanced-Endo's approach has been developed already to further accelerate the computation of free-surface Green's function.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The project has been smoothly carried out. A multi-body hydrodynamic solver has been successfully developed. The computational efficiency and accuracy have been substantially improved by developing the advanced techniques aforementioned. The computational modeling, verifications, and validations have been published in two SCI-indexed international journals: one prestigious journal with a very high impact factor and another with a moderate impact factor. One more manuscript has been submitted to Applied Ocean Research and is now at the stage of revision. In addition, the work of developing the open-source code FinGreen3D has been awarded the Best Paper Award (2nd place) in the 4th Asian Wave and Tidal Energy Conference (AWTEC 2018) among over 250 attendees.
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| 今後の研究の推進方策 |
Because the computation of a large array of WECs still costs huge computational resources, the developed multi-body hydrodynamic solver will be further enhanced by applying the Interaction Theory (Kagemoto & Yue, 1986; Goo & Yoshida, 1990; Kashiwagi, 2000) and/or the pre-corrected Fast Fourier Transform (pFFT) algorithm to derive an extremely efficient wave-array interaction model.
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