EXPERIMENTAL INVESTIGATION OF OFFSHORE WAVE BUOY PERFORMANCE

The important characteristic of sea waves is their high energy density, which is the highest among renewable energy sources. Having up to 2700 km. of shoreline, Iran has a great potential in construction of offshore wave buoys (hereafter called OWB). In this article a OWB model with the possibility of assembling different buoy configurations is introduced. The system is exposed to regular and irregular waves which are generated using wave maker in a 2D wave tank. Wave energy can be extracted from vertical oscillation of its floating buoy. The device is so designed as to operate in rotational (pitch) mode in addition to vertical (heave) motion. Some experiments are also conducted to demonstrate system performance. Experimental results in different conditions are presented and the effect of different buoy configurations on the system efficiency is studied. Numerical simulations that obtain the hydrodynamic coefficients and dynamic response (the Response Amplitude Operator or simply RAO) of each buoy in waves validate test results that the buoy with highest transfer function obtained in simulations has highest efficiency in power extraction. It is finally shown that the horizontal buoy is the most efficient configuration among other constructed buoys for extracting wave energy. The non-dimensional groups are studied and the output power of a full scale OWB is obtained based on similarity laws.