Effects of the end-stop mechanism on the nonlinear dynamics and power generation of a point absorber in regular waves

2021 ◽  
Vol 242 ◽  
pp. 110123
Author(s):  
Mingsheng Chen ◽  
Panpan Xiao ◽  
Zhibo Zhang ◽  
Liang Sun ◽  
Fen Li
Author(s):  
Segen F. Estefen ◽  
Paulo Roberto da Costa ◽  
Eliab Ricarte ◽  
Marcelo M. Pinheiro

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.


2015 ◽  
Vol 104 ◽  
pp. 370-386 ◽  
Author(s):  
Scott J. Beatty ◽  
Matthew Hall ◽  
Bradley J. Buckham ◽  
Peter Wild ◽  
Bryce Bocking

2020 ◽  
Vol 3 (2) ◽  
pp. 73-82
Author(s):  
Benjamin Schubert ◽  
William S. P. Robertson ◽  
Benjamin S. Cazzolato

The dynamic response of a submerged CETO shaped quasi-point absorbing wave energy converter coupled to a bistable power take off is presented in this study. Whilst the impact of bistability has been shown in a limited number of situations to improve the amount of power generated, many models have been restricted to a single degree of freedom and often ignore drag effects. To overcome these model limitations, a submerged single tether point absorber with a bistable power take off was modelled using both 1 and 3 degrees of freedom. The device was subjected to regular waves and included a simple model of viscous drag. The bistable mechanism was provided by a magnetic dipole model quantified by a dimensionless parameter applicable to any bistable system. The performance of the device was is assessed by the theoretical power generated. Over each model, the previously observed benefit of bistability was not consistently obtained. Simulations of regular waves demonstrated an increase in generated power for suboptimal conditions for some frequencies, while a reduction in generated power was observed in optimal conditions. The performance increase showed strong correlation to the phase relationship between the motion and exciting forces as a result of bistability.


Author(s):  
Jun Umeda ◽  
Hiroki Goto ◽  
Toshifumi Fujiwara ◽  
Tomoki Taniguchi ◽  
Shunji Inoue

This paper presents the experimental evaluation results of power production efficiency of model predictive control (MPC) on a wave energy converter (WEC) with a linear generator in regular and irregular waves. A bottom-fixed WEC of point absorber type was subjected to the WEC model in this paper. To compare the power production efficiency, the power production efficiency of the approximate complex-conjugate control with considering the copper loss (ACL) was also evaluated. In regular waves, the MPC performance was comparable to the ACL one in the power-production amount reasonably. In irregular waves which have narrow band spectral distribution, a same trend as the trend in regular waves was obtained. On the other hand, in irregular waves which have broadband spectral distribution, the MPC was more effective than the ACL. Moreover, Experiments in regular and irregular waves were carried out in the MPC under the constraint of the small heave displacement. The constraint of the displacement was approximately satisfied by the MPC. This is useful in practical operation. It is also investigated experimentally how time horizon affects the performance of the MPC. When the time horizon is short, the power production amount of the MPC increases.


Energies ◽  
2018 ◽  
Vol 11 (3) ◽  
pp. 641 ◽  
Author(s):  
Brecht Devolder ◽  
Vasiliki Stratigaki ◽  
Peter Troch ◽  
Pieter Rauwoens

Author(s):  
A. Toffoli ◽  
A. V. Babanin ◽  
F. Ardhuin ◽  
M. Benoit ◽  
E. M. Bitner-Gregersen ◽  
...  

Laboratory experiments have been carried out in the directional wave tank at Marintek (Norway) to study the nonlinear dynamics of surface gravity waves and the occurrence of extreme events, when the wave field traverses obliquely an ambient current. A condition of partial opposition has been considered. Tests on regular waves have shown that the current can trigger the formation of large amplitude waves. In random wave fields, however, this only results in a weak deviation from the statistical properties observed in absence of a current.


Author(s):  
Paulo Lamarão ◽  
Alexandre Menegazzo ◽  
Leonardo Pazim ◽  
Walter Jesus Paucar Casas ◽  
Vittorio Nardin

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