Nonlinear Time-Domain Simulation of the Heaving-Buoy Type Wave Energy Converter by Using Three-Dimensional Potential Numerical Wave Tank Under Irregular Wave Conditions

2020 ◽  
Author(s):  
Sung-Jae Kim ◽  
Weoncheol Koo ◽  
Moo-Hyun Kim
Keyword(s):  
Wave Energy ◽  
Time Domain ◽  
Three Dimensional ◽  
Wave Energy Converter ◽  
Hydrodynamic Performance ◽  
Numerical Wave Tank ◽  
Energy Converter ◽  
Wave Tank ◽  
Type Wave ◽  
Numerical Wave

Abstract The aim of this paper is to evaluate the hydrodynamic performance of a heaving buoy type wave energy converter (WEC) and power take-off (PTO) system. To simulate the nonlinear behavior of the WEC with PTO system, a three-dimensional potential numerical wave tank (PNWT) was developed. The PNWT is a numerical analysis tool that can accurately reproduce experiments in physical wave tanks. The developed time-domain PNWT utilized the previously developed NWT technique and newly adopted the side wall damping area. The PNWT is based on boundary element method with constant panels. The mixed Eulerian-Lagrangian method (MEL) and acceleration potential approach were adopted to simulate the nonlinear behaviors of free-surface nodes associated with body motions. The PM spectrum as an irregular incident wave condition was applied to the input boundary. A floating or fixed type WEC structure was placed in the center of the computational domain. A hydraulic PTO system composed of a hydraulic cylinder, hydraulic motor and generator was modeled with approximate Coulomb damping force and applied to the WEC system. Using the integrated numerical model of the WEC with PTO system, nonlinear interaction of irregular waves, the WEC structure, and the PTO system were simulated in the time domain. The optimal hydraulic pressure of the PTO condition was predicted. The hydrodynamic performance of the WEC was evaluated by comparing the linear and nonlinear analytical results and highlighted the importance accounting for nonlinear free surfaces.

scholarly journals Development of a Three-Dimensional Fully Nonlinear Potential Numerical Wave Tank for a Heaving Buoy Wave Energy Converter

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Sung-Jae Kim ◽  
Weoncheol Koo
Keyword(s):  
Wave Energy ◽  
Large Amplitude ◽  
Three Dimensional ◽  
Wave Energy Converter ◽  
Numerical Wave Tank ◽  
Energy Converter ◽  
Wave Tank ◽  
Fully Nonlinear ◽  
Nonlinear Potential ◽  
Numerical Wave

The hydrodynamic performance of a vertical cylindrical heaving buoy-type floating wave energy converter under large-amplitude wave conditions was calculated. For this study, a three-dimensional fully nonlinear potential-flow numerical wave tank (3D-FN-PNWT) was developed. The 3D-FN-PNWT was based on the boundary element method with Rankine panels. Using the mixed Eulerian–Lagrangian (MEL) method for water particle movement, nonlinear waves were produced in the PNWT. The PNWT can calculate the wave forces acting on the buoy accurately using an acceleration potential approach. The constant panels and least-square gradient reconstruction method were applied to regridding of computational boundaries. An artificial damping zone was employed to satisfy the open-sea conditions at the end free surface boundaries. The diffraction and radiation problems were solved, and their solutions were confirmed by a comparison with previous studies. The interaction of the incident wave, floating body, and power take-off (PTO) behavior was examined in the time domain using the developed 3D-FN-PNWT. From comparison, the difference between the conventional linear analysis and the nonlinear analysis in large-amplitude waves was examined.

scholarly journals Validation of a CFD-based numerical wave tank model for the power production assessment of the wavestar ocean wave energy converter

2020 ◽  
Vol 146 ◽  
pp. 2499-2516 ◽  
Author(s):  
Christian Windt ◽  
Josh Davidson ◽  
Edward J. Ransley ◽  
Deborah Greaves ◽  
Morten Jakobsen ◽  
...  
Keyword(s):  
Wave Energy ◽  
Power Production ◽  
Wave Energy Converter ◽  
Ocean Wave ◽  
Numerical Wave Tank ◽  
Energy Converter ◽  
Tank Model ◽  
Wave Tank ◽  
Ocean Wave Energy ◽  
Numerical Wave

scholarly journals Establishment of Motion Model for Wave Capture Buoy and Research on Hydrodynamic Performance of Floating-Type Wave Energy Converter

2015 ◽  
Vol 22 (s1) ◽  
pp. 106-111 ◽  
Author(s):  
Hongtao Gao ◽  
Biao Li
Keyword(s):  
Wave Energy ◽  
Structural Parameters ◽  
Absorption Efficiency ◽  
Wave Energy Converter ◽  
Hydrodynamic Performance ◽  
Motion Model ◽  
Energy Converter ◽  
Type Wave ◽  
Energy Absorption Efficiency ◽  
Floating Type

Abstract Floating-type wave energy converter has the advantages of high wave energy conversion efficiency, strong shock resistance ability in rough sea and stable output power. So it is regarded as a promising energy utilization facility. The research on hydrodynamic performance of wave capture buoys is the precondition and key to the wave energy device design and optimization. A simplified motion model of the buoys in the waves is established. Based on linear wave theory, the equations of motion of buoys are derived according to Newton’s second law. The factors of wave and buoys structural parameters on wave energy absorption efficiency are discussed in the China’s Bohai Sea with short wave period and small wave height. The results show that the main factor which affects the dynamic responses of wave capture buoys is the proximity of the natural frequency of buoys to the wave period. And the incoming wave power takes a backseat role to it at constant wave height. The buoys structural parameters such as length, radius and immersed depth, influence the wave energy absorption efficiency, which play significant factors in device design. The effectiveness of this model is validated by the sea tests with small-sized wave energy devices. The establishment methods of motion model and analysis results are expected to be helpful for designing and manufacturing of floating-type wave energy converter.

scholarly journals A Numerical Study on Hydrodynamic Performance of an Inclined OWC Wave Energy Converter with Nonlinear Turbine–Chamber Interaction based on 3D Potential Flow

2020 ◽  
Vol 8 (3) ◽  
pp. 176 ◽  
Author(s):  
Jeong-Seok Kim ◽  
Bo Woo Nam ◽  
Kyong-Hwan Kim ◽  
Sewan Park ◽  
Seung Ho Shin ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Numerical Method ◽  
Water Column ◽  
Wave Energy ◽  
Time Domain ◽  
Potential Flow ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Energy Converter

In this study, a time-domain numerical method based on three-dimensional potential flow was developed to analyze the hydrodynamic characteristics of an inclined oscillating-water-column (OWC) wave energy converter (WEC). A finite element method was applied to solve the potential flow around and inside the OWC chamber. A turbine–chamber interaction was considered to take into account the pressure drop inside the OWC chamber, which is a nonlinear function of airflow speed via turbine operation. The instantaneous pressure drop was updated on the free-surface boundary condition inside the chamber in the time-domain to account for the coupling effect between the turbine and the chamber. The present numerical method was verified by comparing it with the model test results. The hydrodynamic characteristics of an inclined OWC chamber in terms of potential flow, such as the water column motion and the three-dimensional flow distribution around the chamber, were investigated. In terms of hydrodynamic performance, the energy conversion efficiency of the chamber showed a nonlinear response characteristic dependent on the incident wave height. In addition, numerical calculations were carried out to clarify the relationship between the main geometric parameters and the hydrodynamic response of the inclined OWC chamber.

scholarly journals Hydrodynamic performance of a floating breakwater as an oscillating-buoy type wave energy converter

2020 ◽  
Vol 257 ◽  
pp. 113996 ◽  
Author(s):  
Hengming Zhang ◽  
Binzhen Zhou ◽  
Christopher Vogel ◽  
Richard Willden ◽  
Jun Zang ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Hydrodynamic Performance ◽  
Energy Converter ◽  
Type Wave ◽  
Floating Breakwater

Experimental studies and time-domain simulation of a hinged-type wave energy converter in regular waves

2020 ◽  
Vol 15 (1) ◽  
pp. 1-15
Author(s):  
Hongxuan (Heather) Peng ◽  
Wei Qiu ◽  
Wei Meng ◽  
Meng Chen ◽  
Brian Lundrigan ◽  
...  
Keyword(s):  
Wave Energy ◽  
Time Domain ◽  
Experimental Studies ◽  
Wave Energy Converter ◽  
Time Domain Simulation ◽  
Regular Waves ◽  
Energy Converter ◽  
Type Wave
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