Performance Simulation of Wave-Powered Navigational Buoy Using CFD and Experimental Study

Abstract

The article discusses the pneumatic performance of wave-powered navigational buoy through numerical prediction and experimental study. In the proposed NIOT configuration, navigational buoy utilizes wave energy for powering a beacon lamp on top of the buoy beside other oceanographic instruments. The functional requirement of navigational buoy, operational power requirement and the wave climate in the location of deployment decides the dimensions of a navigational buoy. The design of the navigational buoy was carried out to suit an existing Impulse turbine which was tested successfully in previous sea trials on another floating wave energy device of similar capacity. The Oscillating Water Column (OWC) diameter decides the discharge and pressure across the turbine and hence plays a critical role in the overall sizing of navigational buoy. The numerical study was carried out in RANS-based CFD commercial code STAR-CCM+. The article discuses the predicted performance parameters like motion response of the buoy in moored condition, pressure drop across orifice, volumetric flow rate and consequently pneumatic power generated for two OWC sizes of 0.9 and 1.1 m in the proposed buoy configuration in a sea environment. The article also discusses about, experiments that were conducted on scaled down (1:8) physical model of the navigational buoy in the wave flume for the various wave conditions. The article discusses various findings useful in finalizing the design of wave powered navigational buoy as a result of this study.