Optimization of bottom-hinged flap-type wave energy converter for a specific wave rose

Abstract

In this paper, we conducted a numerical analysis on the bottom-hinged flap-type Wave Energy Convertor (WEC). The basic model, implemented through the study using ANSYS-AQWA, has been validated by a three-dimensional physical model of a pitching vertical cylinder. Then, a systematic parametric assessment has been performed on stiffness, damping, and WEC direction against an incoming wave rose, resulting in an optimized flap-type WEC for a specific spot in the Persian Gulf. Here, stiffness is tuned to have a near-resonance condition considering the wave rose, while damping is modified to capture the highest energy for each device direction. Moreover, such sets of specifications have been checked at different directions to present the best combination of stiffness, damping, and device heading. It has been shown that for a real condition, including different wave heights, periods, and directions, it is very important to implement the methodology introduced here to guarantee device performance.

Keywords

wave energy converter / bottom-hinged flap / power take-off system / directional analysis / optimization / wave rose

References

[1] Amiri A, Panahi R, Radfar S. Parametric study of two-body floating-point wave absorber. Journal of Marine Science and Application, 2016, 15(1): 41-49

[2] ANSYS AQWA Brochure, 2015, Available from http://www.ansys.com/-/media/Ansys/corporate/resourcelibrary/brochure/ansys-aqwa-brochure.pdf

[3] Bacelli G, Genest R, Ringwood JV. Nonlinear control of flap-type wave energy converter with a non-ideal power take-off system. Annual Reviews in Control, 2015, 40: 116-126

[4] Caska AJ, Finnigan TD. Hydrodynamic characteristics of a cylindrical bottom-pivoted wave energy absorber. Ocean Engineering, 2008, 35(1): 6-16

[5] Flocard F, Finnigan TD. Laboratory experiments on the power capture of pitching vertical cylinders in waves. Ocean Engineering, 2010, 37(11): 989-997

[6] Folley M, Whittaker TJT, Henry A. The effect of water depth on the performance of a small surging wave energy converter. Ocean Engineering, 2007, 34(8): 1265-1274

[7] Gharangian R, Shafieefar M, Panahi R. Unidirectional wave spectrum models for Chabahar bay, 2015

[8] Gunawardane SP, Kankanamge CJ, Watabe T. Study on the performance of the “pendulor” wave energy converter in an array configuration. Energies, 2016, 9(4): 282-308

[9] Kamkar D, Bhattacharjee J G, Soares C. Scattering of gravity waves by multiple surface-piercing floating membrane. Applied Ocean Research, 2013, 39: 40-52

[10] Kurniawan A, Moan T. Characteristics of a pitching wave absorber with rotatable flap. Energy Procedia., 2012, 20: 134-147

[11] Michailides C, Luan C, Gao Z, Moan T. Effect of flap type wave energy convertors on the response of a semi-submersible wind turbine in operational conditions. Proceedings of the ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering, 2014

[12] Pezzutto P. Extension of 2D second-order irregular waves generation equations to non-continuous wavemaker shapes. Coastal Engineering, 2016, 116: 207-219

[13] Renzi E, Abdolali A, Bellotti G, Dias F. Wave-power absorption from a finite array of oscillating wave surge converters. Renewable Energy, 2014, 63: 55-68

[14] Renzi E, Dias F. Hydrodynamics of the oscillating wave surge converter in the open ocean. European Journal of Mechanics-B/Fluids, 2013, 41: 1-10

[15] Renzi E, Dias, F, 2015a. Mathematical modelling of a flap-type wave energy converter. 32nd International Conference on Ocean, Offshore and Arctic Engineering, Nantes, OMAE2013-10215.

[16] Renzi E, Dias F, 2015b. Relations for a periodic array of flap-type wave energy converters. Applied Ocean Research, 39, 31–39. DOI: 10.1016/j.apor.2012.09.002

[17] Schmitt P, Asmuth H E B. Optimizing power take-off of an oscillating wave surge converter using high fidelity numerical simulations. International Journal of Marine Energy, 2016, 16: 196-208

[18] Tomey-Bozo N, Murphy J, Lewis T, Troch P, Thomas G, 2016. Flap type wave energy converter modelling into a time-dependent mild-slope equation model. Proceeding of the 2nd International Conference on Renewable energies Offshore, Lisbon, 277–284.

[19] Wei Y, Rafiee A, Henry A, Dias F. Wave interaction with an oscillating wave surge converter, Part I: Viscous effects. Ocean Engineering, 2015, 104: 185-203

[20] Wei Y, Rafiee A, Henry A, Dias F. Wave interaction with an oscillating wave surge converter, Part II: slamming. Ocean Engineering, 2016, 113: 319-334

[21] Whittaker T, Folley M. Optimisation of wave power devices towards economic wave power systems. Proceedings of the World Renewable Energy Congress, 2010

[22] Wolgamot HA, Fitzgerald CJ. Nonlinear hydrodynamic and real fluid effects on wave energy converters. Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy, 2015, 229(7): 772-794

[23] Xiros NI, Dhanak MR, 2016. Ocean Wave Energy Conversion Concepts. In: Xiros NI, Dhanak MR (Eds.). Springer Handbook of Ocean Engineering. Springer-Verlag, Berlin Heidelberg, 1117–1146.

[24] Yeylaghi S, Moa B, Oshkai P, Buckham B, Crawford C. ISPH modelling of an oscillating wave surge converter using an OpenMP-based parallel approach. Journal of Ocean Engineering and Marine Energy, 2016, 2(3): 301-312

[25] Zhao H, Sun ZL, Hao CL, Shen JF. Numerical modeling on hydrodynamic performance of a bottom-hinged flap wave energy converter. China Ocean Engineering, 2013, 27(1): 73-86