Hydrodynamic Response of One-Body and Two-Body Point Absorber Coupled with Catenary and Taut Mooring Lines in Low Wave Condition

2021 ◽  
Author(s):  
Mohd Amin Hakim Ramli ◽  
Muhammad Adli Mustapa ◽  
Engku Ahmad Azrulhisham Engku Mohamed ◽  
Rohaizad Hafidz Rozali
Keyword(s):  
Mooring Lines ◽  
Wave Condition ◽  
Point Absorber ◽  
Hydrodynamic Response ◽  
Body Point

Effects of the Mooring Line Configuration on the Dynamics of a Point Absorber

2013 ◽  
Author(s):  
Vincenzo Nava ◽  
Marin Rajic ◽  
Carlos Guedes Soares
Keyword(s):  
Case Studies ◽  
Time Instant ◽  
Floating Body ◽  
Mooring Line ◽  
Mooring Lines ◽  
Point Absorber ◽  
Line Configuration ◽  
Frequency Domains ◽  
Restoring Forces ◽  
Static Approach

The aim of this paper is to study the dynamics of a floating body with characteristics comparable to a point absorber wave energy converter with different mooring systems, in geometrical configuration or in the materials. To this purpose, the dynamics of a moored buoy is investigated. The point absorber is modeled as a spherical buoy in plane two-dimensional motion, and it is studied under the action of irregular unidirectional wind-generated waves, moored to the seabed by means of one, two or three mooring lines. Two different sets of moorings are considered, and typical wires and chains used in offshore technology are considered, leading to a total of 6 case studies. A quasi-static approach is used for modeling the restoring forces needed to keep buoy into station, using an innovative iterative procedure able to predict for each time instant and for each cable the lay down length of the cable, being each mooring line allowed to be taut or slack. Approaches in the time and frequency domains are used to obtain the system responses in intermediate waters, where these facilities are usually installed. Results for all case studies are compared both in terms of statistics of response and tensions on the top of the cable.

scholarly journals Ocean Wave-Structure Interaction of Two Wave Energy Converters in Malaysian Water

2018 ◽  
Vol 203 ◽  
pp. 01010
Author(s):  
Ng ChengYee ◽  
Tuhaijan Siti Nor Adha ◽  
Velluruzhathil John Kurian ◽  
Lim Wai Loon
Keyword(s):  
Renewable Energy ◽  
Wave Energy ◽  
Wave Structure ◽  
Separation Distance ◽  
Ocean Wave ◽  
Mooring Lines ◽  
Rapid Urbanization ◽  
Array Configuration ◽  
Point Absorber ◽  
Heave Motion

Due to rapid urbanization and industrialization, the consumption of electricity in the world is expected to increase, thus leads to the fast development of the renewable energy industry. In 2016, 24.5% of the electricity is produced by renewable energy. There are several types of renewable energy, e.g. solar, wind, and ocean wave. The ocean wave energy is identified to have the greatest potential for electricity generation. There are various types of wave energy converter (WEC) that have been designed for harnessing the wave energy, e.g. the oscillating water column, salter duck, point absorber, water dagon etc. Due to the smaller dimension, the point absorber is the most suitable WEC to be deployed in an array configuration, whereby each isolated WEC interacts and alters the vicinity of the wave formation by absorbing, radiating, and diffracting the wave. Subsequently, the wave interference will also affect the WEC’s performance. The objective of the present study is to investigate the optimum separation distance, d, that would resulting to an optimum performance between two WECs in an array configuration using a computational fluid dynamics (CFD) software. The analysis considered an isolated WEC and two WECs, i.e. the heaving point absorbers with three point catenary mooring lines. The influence of the separation distance towards diffraction and response amplitude operator (RAO) of an array of two WECs was evaluated. The optimum production of the wave energy by the heaving point absorber is observed to be highly dependant on the relative heave motion of the two WECs [1]. In the present study, it shows that the optimum distance between two WECs in an array configuration is 20 m, whereby the maximum heave RAO were identified.

Hydrodynamic Response of Multiple Fish Cages Under Wave Loads

2014 ◽  
Author(s):  
Ke Hu ◽  
Shixiao Fu ◽  
Yuwang Xu ◽  
Leixin Ma ◽  
Yifan Chen
Keyword(s):  
Element Model ◽  
Mooring Line ◽  
Wave Loads ◽  
Fish Farms ◽  
Mooring Lines ◽  
Marine Aquaculture ◽  
Wave Propagation Direction ◽  
Environmental Loads ◽  
Hydrodynamic Response ◽  
Fish Cages

Nowadays, marine aquaculture is playing an important role in meeting people’s ever increasing need for sea foods high in protein. The multiple fish cages are commonly used in large fish farms currently. Mooring systems in these fish cages should be strong enough to withstand extreme environmental loads. Thus, a reliable mooring system is required in designing safe structures. In this paper, a finite element model is built. The floating collar is simulated by the beam element, the twine of the net and the mooring lines are simulated by the truss elements. The geometric nonlinearity of the net model and the material nonlinearity of the mooring line are considered. In this analysis, the hydrodynamic forces estimated by Morison equations are applied to the model. The hydrodynamic response of multiple fish cages under the wave loads by considering the pretension of mooring line is carefully studied. The maximum tension in mooring lines under different wave propagation direction is also analyzed in this study.

scholarly journals A Design Outline for Floating Point Absorber Wave Energy Converters

2014 ◽  
Vol 6 ◽  
pp. 846097 ◽  
Author(s):  
Mohammed Faizal ◽  
M. Rafiuddin Ahmed ◽  
Young-Ho Lee
Keyword(s):  
Wave Energy ◽  
Power Output ◽  
Energy Resource ◽  
Wave Structure ◽  
Floating Point ◽  
Mooring Lines ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Incident Waves ◽  
Energy Converters

An overview of the most important development stages of floating point absorber wave energy converters is presented. At a given location, the wave energy resource has to be first assessed for varying seasons. The mechanisms used to convert wave energy to usable energy vary for different wave energy conversion systems. The power output of the generator will have variations due to varying incident waves. The wave structure-interaction leads to modifications in the incident waves; thus, the power output is also affected. The device has to be stable enough to prevent itself from capsizing. The point absorber will give optimum performance when the incident wave frequencies correspond to the natural frequency of the device. The methods for calculating natural frequencies for pitching and heaving systems are presented. Mooring systems maintain the point absorber at the desired location. Various mooring configurations as well as the most commonly used materials for mooring lines are discussed. An overview of scaled modelling is also presented.

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