Effect of a straight coast on the hydrodynamics and performance of the Oscillating Wave Surge Converter

This paper describes the behaviour of a flap-type oscillating wave energy converter near a straight coast. The mathematical formulation is based on a linear potential flow model. Application of Green’s theorem to a semi-infinite fluid domain yields a hypersingular integral equation for the velocity potential which is solved using a series expansion of Chebyshev polynomials. Extremes in the hydrodynamic characteristics of the system are shown to occur at certain wave periods when the device is located at specific distances from the coast. This dynamics can have either detrimental or favourable effects on the performance of the converter, depending on the system parameters. Surprisingly, when the device is located very close to the coast, the qualitative behaviour of the system resembles that of a single device in the open ocean. In addition, the analysis shows that under such circumstances, the device consistently achieves much higher levels of efficiency than it would achieve in an open ocean

Wave farm modelling of oscillating wave surge converters

A mathematical model is described to analyse the hydrodynamic behaviour of a wave energy farm consisting of oscillating wave surge converters in oblique waves. The method is a highly efficient semi-analytical approach based on the linear potential flow theory. Wave farms with a large number of such devices are studied for various configurations. For an inline configuration with normally incident waves, the occurrence of a near-resonant behaviour, already known for small arrays, is confirmed. A strong wave focusing effect is observed in special configurations comprising a large number of devices. The effects of the arrangement and of the distance of separation between the flaps are also studied extensively. In general, the flaps lying on the front of the wave farm are found to exhibit an enhanced performance behaviour in average, owing to the mutual interactions arising within the array. A random sea analysis shows that a slightly staggered arrangement can be an ideal layout for a wave farm of this device. The hydrodynamics of two flaps that oscillate back to back is also discussed

Analytical and computational modelling for wave energy systems: the example of oscillating wave surge converters

The development of new wave energy converters has shed light on a number of unanswered questions in fluid mechanics, but has also identified a number of new issues of importance for their future deployment. The main concerns relevant to the practical use of wave energy converters are sustainabiliy, survivability, and maintainability. And of course, it is also necessary to maximize the capture per unit area of the structure as well as to minimize the cost. In this review, we consider some of the questions related to the topics of sustainability, survivability, and maintenance access, with respect to sea conditions, for generic wave energy converters with an emphasis on the oscillating wave surge converter (OWSC). New analytical models that have been developed are a topic of particular discussion. It is also shown how existing numerical models have been pushed to their limits to provide answers to open questions relating to the operation and characteristics of wave energy converters

Effect of a straight coast on the hydrodynamics and performance of the Oscillating Wave Surge Converter

This paper was accepted for publication in the journal Ocean Engineering and the definitive published version is available at http://dx.doi.org/10.1016/j.oceaneng.2015.05.025This paper describes the behaviour of a flap-type oscillating wave energy converter near a straight coast. The mathematical formulation is based on a linear potential flow model. Application of Green’s theorem to a semi-infinite fluid domain yields a hypersingular integral equation for the velocity potential which is solved using a series expansion of Chebyshev polynomials. Extremes in the hydrodynamic characteristics of the system are shown to occur at certain wave periods when the device is located at specific distances from the coast. This dynamics can have either detrimental or favourable effects on the performance of the converter, depending on the system parameters. Surprisingly, when the device is located very close to the coast, the qualitative behaviour of the system resembles that of a single device in the open ocean. In addition, the analysis shows that under such circumstances, the device consistently achieves much higher levels of efficiency than it would achieve in an open ocean

Analytical and computational modelling for wave energy systems:the example of oscillating wave surge converters

This is an Open Access Article. It is published by Springer under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/The development of new wave energy converters has shed light on a number of unanswered questions in fluid mechanics, but has also identified a number of new issues of importance for their future deployment. The main concerns relevant to the practical use of wave energy converters are sustainabiliy, survivability, and maintainability. And of course, it is also necessary to maximize the capture per unit area of the structure as well as to minimize the cost. In this review, we consider some of the questions related to the topics of sustainability, survivability, and maintenance access, with respect to sea conditions, for generic wave energy converters with an emphasis on the oscillating wave surge converter (OWSC). New analytical models that have been developed are a topic of particular discussion. It is also shown how existing numerical models have been pushed to their limits to provide answers to open questions relating to the operation and characteristics of wave energy converters

Mathematical modeling and optimization of wave energy converters and arrays

The aim of this work is to develop methodologies and understand the dynamics of waveenergy energy converters (WECs) in some problems of practical interest. The focus is ona well known WEC - the Oscillating Wave Surge Converter (OWSC). In the first work, amathematical model is described to analyze the interactions in a wave energy farm comprising of OWSCs. The semi-analytical method uses Green’s integral equation formulation and Green’s function, yielding hyper-singular integrals which are later solved using the Chebyshev polynomial of the second kind. A new methodology for the optimization of large wavefarms is then presented and the approach includes a statistical emulator, an active learning approach (Gaussian Process Upper Confidence Bound with Pure Exploration) and a genetic algorithm. The modular concept of the OWSC, which has emerged to address some of the shortcomings in the original design of the OWSC, is also described and investigated using a semi analytical approach for cylindrical modules. In another work, the dynamics of the OWSC near a straight coast is analyzed and for a particular case, a significant enhancement in the performance of the OWSC is observed. This interesting result motivated the following study, where it is investigated if a breakwater can artificially enhance the performance of the OWSC. Lastly, a new approach is presented to analyze the interactions between two different kind of WECs (an OWSC and a Heaving Wave Energy Converter), performing different modes of motion.A hard copy of this thesis is available in UCD Library, thesis 1303

spatio_temporal_tidal_current_GP.zip

<div>The code presented is just one of the examples of the case studies performed in the work. </div><div>For this particular code the GPhour sampling strategy is used.  </div><div>A general code can be availed from the authors on request.</div><div><br></div><div><br></div><div>Before running the code, first UTide matlab files must be downloaded from online sources and placed in the UTide folder. </div><div><br></div><div>There are three UTide files that must be placed in the UTide folder:</div><div>1) ut_solv.m</div><div>2) ut_reconstr.m</div><div>3) ut_constants.mat</div><div><br></div><div>The UTide code makes the harmonic analysis computations.</div><div><br></div><div><br></div><div>To execute the code, run the run_code.m file in the main folder. </div><div>The file prediction.m is used for computing the predictions, making plots and determining the mean squared error.</div