By-pass air-valve control of an OWC wave power plant

The paper deals with the numerical simulation of the performance of an oscillating-water-column (OWC) wave power plant equipped with a by-pass valve whose role is to prevent the turbine flow rate from exceeding the stall-free operating conditions. Continuous and step-wise valve area changes are considered, the second case corresponding to multi-element design. The adequacy of the valve and of its control is assessed through the gain in annual electrical energy, and the total number of required valve strokes. The following items are separately analyzed: (i) number of (identical) valve elements; (ii) valve response time; (iii) signal noise level in chamber air-pressure measurements due to large-eddy, turbulence; (iv) valve's control algorithm.