Coast/breakwater-integrated OWC: A theoretical model

Zheng, Siming; Zhang, Yongliang; Iglesias, G.

doi:10.1016/j.marstruc.2019.04.001

Cited by 104 publications

(34 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…From the above discussions, we have seen that to get horizontal exciting forces, we have to evaluate the associated unknown coefficients appearing in the expressions of potentials given by the Eq. (22-24) with the help of matching conditions (18)(19)(20)(21). As every expression of potential is found to be a series with infinite terms, therefore, calculate the corresponding values, we must be truncated appropriately after some terms.…”

Section: Numerical Results and Conclusionmentioning

confidence: 99%

“…Zhu and Mitchell [20] solved the problem of diffraction of ocean wave by a hollow cylinder in an ocean of uniform depth and they used Galkerin's method to find the analytical solution of this problem. Zheng et al [21] investigated the fulfilment of an oscillating water column(OWC) over a vertical structure in uniform water depth. the have valodated their results and then model is used to study the effect of the thickness of the chamber wall and the radius.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Wave loads by an oscillating water column in presence of bottom-mounted obstacle in the channel of finite width

Borah

Hassan

2019

SN Appl. Sci.

View full text Add to dashboard Cite

In the present study, we solved the problem of diffraction in water waves with consists of a pair of vertical cylinders in a channel having finite width. It consists of a partially submerged floating hollow cylinder place above a fixed coaxial bottom-mounted obstacle. With the help of matched eigenfunction expansion, channel multipole and variables separation methods, the analytical expression of potentials are obtained. Using these analytical expressions of diffracted velocity potentials, we can derive the expressions of exciting forces exerted by the cylinders. The influence of various parameters viz draft of the hollow cylinder, radius of the cylinders, the gap between the cylinders and the width of the channel walls on the exciting forces have been investigated. The results have been validated by comparing our results with available results. All the observations are validated through suitable graphs.

show abstract

Section: Numerical Results and Conclusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wave loads by an oscillating water column in presence of bottom-mounted obstacle in the channel of finite width

Borah

Hassan

2019

SN Appl. Sci.

View full text Add to dashboard Cite

show abstract

“…Figure 8 displays the frequency responses of the hydrodynamic coefficients for two coast-integrated OWCs, the same OWCs in the open sea and a single coast-integrated/offshore OWC (Zheng et al. 2018, 2019). For all four cases in the full range of , is positive (figure 8 a ), which is reasonable from the perspective of energy conservation and outgoing propagation of radiated waves (Zheng & Zhang 2018).…”

Section: Resultsmentioning

confidence: 99%

“…More recently, Zheng, Zhang & Iglesias (2019) developed a theoretical model of a coast/breakwater-integrated OWC, in which the effect of the thickness of the OWC chamber wall was considered. Subjected to a fixed outer radius, the thinner the chamber wall, the larger and broader the main peaks of the frequency response of wave power capture width.…”

Section: Introductionmentioning

confidence: 99%

Wave power extraction from multiple oscillating water columns along a straight coast

et al. 2019

Self Cite

View full text Add to dashboard Cite

The integration of oscillating water column (OWC) wave energy converters into a coastal structure (breakwater, jetty, pier, etc.) or, more generally, their installation along the coast is an effective way to increase the accessibility of wave power exploitation. In this paper, a theoretical model is developed based on the linear potential flow theory and eigenfunction matching method to evaluate the hydrodynamic performance of an array of OWCs installed along a vertical straight coast. The chamber of each OWC consists of a hollow vertical circular cylinder, which is half embedded in the wall. The OWC chambers in the theoretical model may have different sizes, i.e. different values of the radius, wall thickness and submergence. At the top of each chamber, a Wells turbine is installed to extract power. The effects of the Wells turbine together with the air compressibility are taken into account as a linear power take-off system. The hydrodynamic and wave power extraction performance of the multiple coast-integrated OWCs is compared with that of a single offshore/coast-integrated OWC and of multiple offshore OWCs. More specifically, we analyse the role of the incident wave direction, chamber size (i.e. radius, wall thickness and submergence), spacing between OWCs and number of OWCs by means of the present theoretical model. It is shown that wave power extraction from the coast-integrated OWCs for a certain range of wave conditions can be significantly enhanced due to both the constructive array effect and the constructive coast effect.

show abstract

“…One of the objectives of this study is to integrate a breakwater with a WEC for functional complementation and cost-sharing. For a hybrid breakwater-WEC system, preliminary investigation under regular waves is often necessary to examine its performance [18][19][20]. Thereby, the hydrodynamic characteristics of the developed system for wave energy extraction from regular waves and for wave attenuation are investigated in an experimental manner.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Performance of a Hybrid System Combining a Fixed Breakwater and a Wave Energy Converter: An Experimental Study

et al. 2020

View full text Add to dashboard Cite

In this paper, a hybrid system integrating a fixed breakwater and an oscillating buoy type wave energy converter (WEC) is introduced. The energy converter is designed to extract the wave power by making use of the wave-induced heave motions of the three floating pontoons in front of the fixed breakwater. A preliminary experimental study is carried out to discuss the hydrodynamic performance of the hybrid system under the action of regular waves. A scale model was built in the laboratory at Hohai University, and the dissipative force from racks and gearboxes and the Ampere force from dynamos were employed as the power take-off (PTO) damping source. During the experiments, variations in numbers of key parameters, including the wave elevation, free response or damped motion of the floating pontoons, and the voltage output of the dynamos were simultaneously measured. Results indicate that the wave overtopping and breaking occurring on the upper surfaces of floating pontoons have a significant influence on the hydrodynamic performance of the system. For moderate and longer waves, the developed system proves to be effective in attenuating the incident energy, with less than 30% of the energy reflected back to the paddle. More importantly, the hydrodynamic efficiency of energy conversion for the present device can achieve approximately 19.6% at the lowest wave steepness in the model tests, implying that although the WEC model harnesses more energy in more energetic seas, the device may be more efficient for wave power extraction in a less energetic sea-state.

show abstract

Coast/breakwater-integrated OWC: A theoretical model

Cited by 104 publications

References 36 publications

Wave loads by an oscillating water column in presence of bottom-mounted obstacle in the channel of finite width

Wave loads by an oscillating water column in presence of bottom-mounted obstacle in the channel of finite width

Wave power extraction from multiple oscillating water columns along a straight coast

Hydrodynamic Performance of a Hybrid System Combining a Fixed Breakwater and a Wave Energy Converter: An Experimental Study

Contact Info

Product

Resources

About