Hydrodynamics of onshore oscillating water column devices: A numerical study using smoothed particle hydrodynamics

Abstract

Oscillating water column (OWC) device is possibly the most studied among various wave energy converters and many different realizations of the technology have been investigated. To study the complex hydrodynamic behaviour of an OWC, a two-dimensional numerical wave tank based on the weakly compressible smoothed particle hydrodynamics (SPH) method is developed in this paper. A simplified pneumatic model is proposed here to simulate the effect induced by a pneumatic power take-off system within the framework of a single-phase SPH model, and implemented to determine the air pressure imposed on the free surface inside the OWC chamber. Additionally, a regional ghost particle approach, as boundary condition in SPH, is proposed to better simulate fluid dynamics near a thin wall. The overall computation cost is reduced dramatically due to the employment of the regional ghost particle boundary condition method. First, the numerical model is validated under regular waves using published physical and numerical data. An extensive campaign of computational tests is then carried out, studying the performance of the OWC for various wall thicknesses and damping coefficient under various wave conditions. The results demonstrate that the present SPH model can be used as a practical tool for the development of high-performance OWCs.