2015 Volume 3 Issue 1 Pages 93-104
A two-dimensional frequency-domain numerical analysis on the primary conversion efficiency of multi-chamber Oscillating Water Columns (OWCs) is presented. The numerical model is developed by combining the hydrodynamics of the interaction between the wave and the OWC and the thermodynamics of the air chambers. The wave-induced force is calculated using the boundary element method based on the velocity potential theory. The air flow is studied using mass and energy conservation equations and an equation of state. The air pressure in the air chambers, the reflection coefficient, and the primary conversion efficiency of each of the chambers, as well as the combined efficiency, are evaluated using the boundary integral equations. In addition, the behavior of these physical quantities, along with the variations in the nozzle ratio, the relative water depth, the depth of the curtain wall, and the width of the front-chamber are investigated using the calculated results.