HYDRODYNAMIC INVESTIGATION OF A NOVEL CONCEPT OF OWC TYPE WAVE ENERGY CONVERTER DEVICE

2021 ◽  
pp. 1-22
Author(s):  
Kourosh Rezanejad ◽  
Carlos Guedes Soares
Keyword(s):  
Water Column ◽  
Wave Theory ◽  
The Body ◽  
Hydrodynamic Performance ◽  
Bottom Plate ◽  
Linear Wave ◽  
Oscillating Water Column ◽  
Wave Direction ◽  
Linear Wave Theory ◽  
Novel Concept

Abstract The hydrodynamic performance of a novel and efficient concept of a floating Oscillating Water Column device has been investigated. The new concept consists of two chambers. These chambers are positioned on the upstream (fore chamber) and on the downstream (rear chamber) of the incident wave direction. The rear chamber acts mainly similar to a Backward Bent Duct Buoy system, while the design of the fore chamber follows conventional types of Oscillating Water Column systems with the harbour plates (bottom plate as well as side plates) elongated outside of the fore chamber. The primary efficiency of the devised concept has been investigated in the frequency domain. In this context, to solve the corresponding diffraction and radiation problems due to the influence of the air pressure inside the chambers as well as motions of the body, an in-house code has been developed in 2D using the Boundary Element Method based on linear wave theory. The obtained numerical results show that the introduced concept has advanced hydrodynamic efficiency in a broad range of waves.

Hydrodynamic Investigation of a Novel Concept of OWC Type Wave Energy Converter Device

2019 ◽  
Author(s):  
Kourosh Rezanejad ◽  
Carlos Guedes Soares
Keyword(s):  
Water Column ◽  
Wave Theory ◽  
The Body ◽  
Hydrodynamic Performance ◽  
Bottom Plate ◽  
Linear Wave ◽  
Oscillating Water Column ◽  
Wave Direction ◽  
Linear Wave Theory ◽  
Novel Concept

Abstract In the present study, the hydrodynamic performance of a novel and efficient concept of a floating Oscillating Water Column device has been investigated. The new concept consists of two chambers that are placed in the upstream (fore chamber) and in the downstream (rear chamber) with respect to the incident wave direction. The rear chamber acts mainly similar to a Backward Bent Duct Buoy system, while the design of the fore chamber follows conventional types of Oscillating Water Column systems with the harbour plates (bottom plate as well as side plates) elongated outside of the fore chamber. The primary efficiency of the devised concept has been investigated in the frequency domain. In this context, to solve the corresponding diffraction and radiation problems due to the influence of the air pressure inside the chambers as well as motions of the body, an in-house code has been developed in 2D using the Boundary Element Method based on linear wave theory. The obtained numerical results show that the introduced concept has advanced hydrodynamic efficiency in a broad range of waves.

scholarly journals A Theoretical Study of the Hydrodynamic Performance of an Asymmetric Fixed-Detached OWC Device

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2637
Author(s):  
Ayrton Alfonso Medina Rodríguez ◽  
Rodolfo Silva Casarín ◽  
Jesús María Blanco Ilzarbe
Keyword(s):  
Vertical Wall ◽  
Expansion Method ◽  
Wave Theory ◽  
Hydrodynamic Performance ◽  
Linear Wave ◽  
Low Frequencies ◽  
Linear Wave Theory ◽  
Hydrodynamic Efficiency ◽  
Eigenfunction Expansion Method ◽  
Good Agreement

The chamber configuration of an asymmetric, fixed-detached Oscillating Water Column (OWC) device was investigated theoretically to analyze its effects on hydrodynamic performance. Two-dimensional linear wave theory was used, and the solutions for the associated radiation and scattering boundary value problems (BVPs) were derived through the matched eigenfunction expansion method (EEM) and the boundary element method (BEM). The results for the hydrodynamic efficiency and other important hydrodynamic properties were computed and analyzed for various cases. Parameters, such as the length of the chamber and the thickness and submergence of the rear and front walls, were varied. The effects on device performance of adding a step under the OWC chamber and reflecting wall in the downstream region were also investigated. A good agreement between the analytical and numerical results was found. Thinner walls and low submergence of the chamber were seen to increase the efficiency bandwidth. The inclusion of a step slightly reduced the frequency at which resonance occurs, and when a downstream reflecting wall is included, the hydrodynamic efficiency is noticeably reduced at low frequencies due to the near trapped waves in the gap between the OWC device and the rigid vertical wall.

scholarly journals Wave power extraction from a bottom-mounted oscillating water column converter with a V-shaped channel

2014 ◽  
Vol 470 (2167) ◽  
pp. 20140074 ◽  
Author(s):  
Zhengzhi Deng ◽  
Zhenhua Huang ◽  
Adrian W. K. Law
Keyword(s):  
Water Column ◽  
Water Depth ◽  
Wave Energy ◽  
High Efficiency ◽  
Expansion Method ◽  
Opening Angle ◽  
Energy Extraction ◽  
Oscillating Water Column ◽  
Wave Direction ◽  
Power Extraction

An analytical theory is developed for an oscillating water column (OWC) with a V-shaped channel to improve the pneumatic efficiency of wave energy extraction. An eigenfunction expansion method is used in a cylindrical coordinate system to investigate wave interaction with the OWC converter system. Auxiliary functions are introduced to capture the singular behaviours in the velocity field near the salient corners and cusped edges. Effects of the OWC dimensions, the opening angle and length of the V-shaped channel, as well as the incident wave direction, on the pneumatic efficiency of wave energy extraction are examined. Compared with a system without the V-shaped channel, our results show that the V-shaped channel can significantly increase the conversion efficiency and widen the range of wave frequency over which the OWC system can operate at a high efficiency. For typical coastal water depths, the OWC converter system can perform efficiently when the diameter of the OWC chamber is in the range of 1 5 – 1 2 times the water depth, the opening angle of the V-shaped channel is in the range of [ π /2, 3 π /4] and the length of the V-shaped channel is in the range of 1–1.5 times the water depth.

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