Experimental and numerical study of a circular OWC with a U-shaped duct for wave energy conversion in long waves: Hydrodynamic characteristics and viscous energy loss

Journal Article

Title: Experimental and numerical study of a circular OWC with a U-shaped duct for wave energy conversion in long waves: Hydrodynamic characteristics and viscous energy loss

Author:

Xu, C.; He, Y.; Yao, Y.; Zuo, J.

Publication Date:

October 1, 2023

Journal:

Renewable Energy

Volume:

215

Publisher:

Elsevier

Affiliation:

Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha University of Science & Technology

Technology:

Wave, Oscillating Water Column

Collection Method:

Lab Data, Modeling

Engineering:

Hydrodynamics, Power Take Off

Document Access

Website:

External Link

Citation

Xu, C.; He, Y.; Yao, Y.; Zuo, J. (2023). Experimental and numerical study of a circular OWC with a U-shaped duct for wave energy conversion in long waves: Hydrodynamic characteristics and viscous energy loss. Renewable Energy, 215 https://doi.org/10.1016/j.renene.2023.06.022

Abstract

This paper presents an experimental and numerical study of a pile-type circular oscillating water column device with a U-shaped duct (circular U-OWC) for wave energy conversion in long waves. In the experiments, the circular U-OWC model and a conventional OWC model of identical chamber dimension was compared in a wave flume under various wave conditions. Orifices of different sizes are used to simulate the power-takeoff (PTO). The pneumatic power, PTO damping coefficient, and the scattering of the incident waves are measured. A RANS equation based numerical model with a modified k-w SST turbulence closure is validated using the experiment. The numerical model is utilized to investigate the spatial non-uniformity of the free surface inside the chamber, and the viscous energy loss in the U-shaped duct. It is found that for long waves, the circular U-OWC device is several times more efficient than a conventional OWC device, and the sloshing effect inside the pneumatic chamber is significantly reduced compared to a conventional OWC device. It is also found that a significant amount of energy entering the U-shaped duct is dissipated in viscous loss, recommendations on U-shaped duct design are given to help reduce the viscous loss of the device.