scholarly journals A FARM OF WAVE ACTIVATED BODIES FOR COASTAL PROTECTION PURPOSES

2012 ◽  
Vol 1 (33) ◽  
pp. 68 ◽  
Author(s):  
Elisa Angelelli ◽  
Barbara Zanuttigh
Keyword(s):  
Numerical Modelling ◽  
Numerical Simulations ◽  
Transmission Coefficient ◽  
Wave Energy ◽  
Numerical Results ◽  
Experimental Results ◽  
Coastal Protection ◽  
Basic Module ◽  
Wave Energy Converters ◽  
Mike 21

This paper aims at investigating the efficacy of a floating farm of wave energy converters for coastal protection purposes through physical and numerical modelling. The experiments were performed in 3D conditions on a basic module consisting of two staggered lines and three devices. The numerical simulations were carried out with the software MIKE 21 BW, developed by DHI Water & Environment & Health, and were calibrated based on the experimental results. Additional configurations were tested by varying the gap long-shore width and the device alignment. Despite the model limitations, i.e. the representation of the devices as fixed porous piles, the numerical results well approximate the average measured transmission coefficient and allow to derive a complete map of the hydrodynamics around the devices.

scholarly journals WAVE ENERGY CONVERSION USING A BLOW-JET SYSTEM

2011 ◽  
Vol 1 (32) ◽  
pp. 62 ◽  
Author(s):  
Edgar Mendoza-Baldwin ◽  
Rodolfo Silva-Casarín ◽  
Rafael Sánchez-Dirzo ◽  
Xavier Chávez-Cárdenas
Keyword(s):  
Potential Energy ◽  
Transmission Coefficient ◽  
Experimental Work ◽  
Wave Energy ◽  
Wave Climate ◽  
Coastal Protection ◽  
Wave Energy Conversion ◽  
Wave Energy Converters ◽  
Geometric Designs ◽  
Real Chance

This paper presents the results of exhaustive experimental work focused on evaluating the efficiency of two devices as wave energy converters and as coastal protection alternatives. The first device is a wave amplifier that by means of overtopping stores water in a reservoir where potential energy can be used to produce power. The second device, the Blow-Jet, is a novel proposal that gathers together the operation of a tapchan and a blowhole to generate an intermittent jet that can easily feed a turbine. Results show that for both devices there is a strong dependency on the wave climate but that there is a possibility of optimizing geometric designs. Transmission coefficient values obtained for the Blow-Jet point to a real chance for its use as a multi-purpose coastal structure.

Effects of Scale and Configuration of Air Chamber of OWC Type WECs on Air Chamber Characteristics

2020 ◽  
Author(s):  
Tomoki Ikoma ◽  
Shota Hirai ◽  
Yasuhiro Aida ◽  
Koichi Masuda ◽  
Hiroaki Eto
Keyword(s):  
Numerical Calculation ◽  
Water Column ◽  
Wave Energy ◽  
Experimental Models ◽  
Experimental Results ◽  
Oscillating Water Column ◽  
Wave Energy Converters ◽  
Air Chamber ◽  
The Difference ◽  
Energy Converters

Abstract This paper describes scale effects and influence of configurations of oscillating water column type wave energy converters from model tests and theoretical calculations. Many researches regarding wave energy converters (WECs) have been conducted. The behavior of an oscillating water column of an OWC type WEC is complicated because of including wave-air-turbine interaction, and thus several issues remain. One of the issues is that influence of difference in scale between small scale experimental models and full scale models is unclear. It is important to understand its characteristics accurately to improve design technologies for such as complicated systems. In this study, we carried out forced oscillation tests using multiple scales and shapes of OWC models in still water, and measured the pressure inside the air chamber and the internal mean water level with a multi-line wave probe. The experimental models used have a box like air chamber or manifold type air chamber, and which scales were 1/1, 1/2 and 1/4.The difference of the two air chambers is an orifice or a duct to be inlet-outlet of air. As a result, the difference in scale and configuration of the air chamber affected the characteristics of the air chamber. In addition, as a result of numerical calculation using the linear potential theory and comparison with experimental results, the experimental results could be reproduced by numerical calculation. Besides, we could discuss the effects and the influences of the air chamber basically.

scholarly journals NEAR-SHORE FLOATING WAVE ENERGY CONVERTERS: APPLICATIONS FOR COASTAL PROTECTION

2011 ◽  
Vol 1 (32) ◽  
pp. 61 ◽  
Author(s):  
Piero Ruol ◽  
Barbara Zanuttigh ◽  
Luca Martinelli ◽  
Peter Kofoed ◽  
Peter Frigaard
Keyword(s):  
Sediment Transport ◽  
Wave Energy ◽  
Coastal Protection ◽  
Transmission Characteristics ◽  
Body Type ◽  
Wave Energy Converters ◽  
Physical Model Tests ◽  
Order Of Magnitude ◽  
Adriatic Coast ◽  
Near Shore

Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency and transmission characteristics are approximated to functions of wave height, period and obliquity. Their order of magnitude are 20% and 80%, respectively. It is imagined that an array of DEXA is deployed in front of Marina di Ravenna beach (IT), a highly touristic site of the Adriatic Coast. Based on the CERC formula, long-shore sediment transport is evaluated in presence and in absence of this array of DEXAs. The sediment transport in this site is quite large and frequently changes directions during the year. The larger North directed contribution and the more persistent South directed one are similar in magnitude and almost compensate each other, with the latter only slightly prevailing. It is shown that the DEXA could be designed so that the effect on sediment transport becomes quite significant and the direction of the net transport can be reversed.

scholarly journals Study of the Planar Rocking-Block Dynamics With Coulomb Friction: Critical Kinetic Angles

2012 ◽  
Vol 8 (2) ◽  
Author(s):  
Hongjian Zhang ◽  
Bernard Brogliato ◽  
Caishan Liu
Keyword(s):  
Numerical Simulations ◽  
Coulomb Friction ◽  
Numerical Scheme ◽  
Numerical Results ◽  
Experimental Results ◽  
Restitution Coefficient ◽  
Rocking Block ◽  
Kinetic Angle ◽  
Multiple Impact ◽  
Impact With Friction

The objective of this paper is to show, through the planar rocking block example, that kinetic angles play a fundamental role in multiple impact with friction. Even in the presence of Coulomb friction, a critical kinetic angle θcr is exhibited that allows one to split the blocks into two main classes: slender blocks with a kinetic angle larger than θcr, and flat blocks with a kinetic angle smaller than θcr. The value of θcr varies with the friction value, but it is independent of the restitution coefficient (normal dissipation). Numerical results are obtained using a multiple impact law recently introduced by the authors. Some comparisons between numerical and experimental results that validate the used model and numerical scheme are presented. However, this paper is mainly based on numerical simulations.

scholarly journals Theoretical and experimental analysis of the exact receptance function of a clamped-clamped beam with concentrated masses

2020 ◽  
Author(s):  
Nguyen Viet Khoa ◽  
Dao Thi Bich Thao
Keyword(s):  
Dynamic Response ◽  
Numerical Simulations ◽  
Experimental Analysis ◽  
Arbitrary Point ◽  
Peak Position ◽  
Numerical Results ◽  
Experimental Results ◽  
Harmonic Force ◽  
Concentrated Masses

This paper establishes the exact receptance function of a clamped-clamped beam carrying concentrated masses. In this paper, the derivation of exact receptance and numerical simulations are provided. The proposed receptance function is convenient to apply for predicting the dynamic response at arbitrary point of the beam acted by a harmonic force applied at arbitrary point. The influence of the concentrated masses on the receptance is investigated. The numerical simulations show that a peak in the receptance decreases when there is a mass located close to that peak position. The numerical results have been compared to the experimental results has to justify the theory.

Numerical Analysis of Oil/water Dispersion Interface Prediction in Horizontal Pipe Separators

2021 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Numerical Simulations ◽  
Volume Fraction ◽  
Water Layer ◽  
Numerical Results ◽  
Experimental Results ◽  
Internal Diameter ◽  
Ansys Fluent ◽  
Horizontal Pipe ◽  
Water Dispersion ◽  
Vof Model

Abstract This paper presents the comparative study of experimental, modeling, and simulation results that are performed using commercially available ANSYS Fluent software to analyze the separation kinetics of oil and water in a horizontal separator at various velocities and watercuts. The horizontal pipe separator used in this study has an internal diameter of 0.0762 m and a length of 10.3 m separating oil and water with specific gravities of 1.0 and 0.857 and watercuts ranging from 20 to 90%. The mixture velocities studied are 0.08, 0.13, and 0.20 m/s. Numerical simulations are done using the hybrid Eulerian-Eulerian multifluid VOF model to study the effect of watercut on the creaming of the oil layer and sedimentation of the water layer respectively. As the mixture velocities increased, the initial length of separation increased like experimental results. As the watercut increased, the separation of water enhanced, while the oil creaming improved with the lowering of the watercut as expected. Numerical results showed good agreement for water/dispersion interface predictions for all the conditions studied. The CFD results are compared against experimental results obtained by Othman in 2010 and agree with the trend of separation. The numerical simulations gave insights into the velocity profiles in each of the layers such as creamed oil, sedimented water, and the layer of emulsion that is not separated. Also, the numerical results are validated against the extended Gassies (2008) model incorporating correlation for turbulent time decay and oil volume fraction proposed by Dabirian et al in 2018.

On the Importance of High–Fidelity Numerical Modelling of Ocean Wave Energy Converters under Controlled Conditions

2022 ◽  
Author(s):  
C. Windt
Keyword(s):  
Numerical Modelling ◽  
Wave Energy ◽  
Numerical Models ◽  
Ocean Wave ◽  
High Fidelity ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
Controlled Conditions ◽  
Hydrodynamic Wave ◽  
Energy Converters

Abstract. Numerical modelling tools are commonly applied during the development and optimisation of ocean wave energy converters (WECs). Models are available for the hydrodynamic wave structure interaction, as well as the WEC sub–systems, such as the power take–off (PTO) model. Based on the implemented equations, different levels of fidelity are available for the numerical models. Specifically under controlled conditions, with enhance WEC motion, it is assumed that non-linearities are more prominent, re- quiring the use of high–fidelity modelling tools. Based on two different test cases for two different WECs, this paper highlights the importance of high–fidelity numerical modelling of WECs under controlled conditions.

scholarly journals Hydrodynamic Performance of Rectangular Heaving Buoys for an Integrated Floating Breakwater

2019 ◽  
Vol 7 (8) ◽  
pp. 239 ◽  
Author(s):  
Xiaoxia Zhang ◽  
Qiang Zeng ◽  
Zhen Liu
Keyword(s):  
Wave Energy ◽  
Numerical Results ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Wave Energy Converters ◽  
Floating Breakwater ◽  
Reaction Forces ◽  
Wave Conditions

Recently, the integrated development of wave energy converters and breakwaters has become popular, moving from traditional passive wave absorption to active energy capture. In this study, rectangular heaving buoys are considered as floating breakwater modules to absorb wave energy. A numerical wave tank is established based on Reynolds Averaged Navier-Stokes equation and User-Define-Function in ANSYS-Fluent commercial software. The numerical results show that incident wave conditions and submerged depth have significant effects on the heaving performance and wave energy absorption of a rectangular buoy. Flow structures around the buoy are shown to exhibit flow separations and vortex shedding, which can provide more information on buoy optimization. Power take-off (PTO) reaction forces are assumed to be a linear function of the translation velocities of the buoy. Numerical results demonstrate that a suitable PTO module can improve the wave power absorption by up to 34.2% for certain buoy and wave conditions, which is valuable for further investigations.

Numerical Analysis of the Influence of the Padding-Plate on the Extended End-Plate Connection

2014 ◽  
Vol 578-579 ◽  
pp. 505-508
Author(s):  
Shao Qin Zhang ◽  
Lei Wu
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Load Capacity ◽  
Numerical Results ◽  
Experimental Results ◽  
End Plate ◽  
Extended End Plate ◽  
Plate Connection

In the present paper, we investigate the effect of a padding-plate on the behavior of extended end-plate semi-rigid connections. The numerical simulations were carried out for a standard extended end-plate connection joint without padding-plate and two connection joints with 4mm and 6mm thick padding-plates. The existing experimental results verified the validity of the numerical model. The numerical results have shown that a thin padding-plate will more or less decline the carrying load capacity of the connection joint but greatly improve the connect ductility. Filling a thin padding-plate in the end-plate connection is feasible and brings the forewarning function.

Sign in / Sign up

Export Citation Format

Share Document