Shape optimization of the flap of wave surge converters

The present environmental issues are alarming the use of conventional sources of energy. This has resulted in urgent studies in improving the methods of harnessing renewable sources of energy. The importance of wave energy arises from the fact that it is easily predictable, consistent and cause less damage to land area. The devices developed for tapping wave energy include wave activated bodies that use orbital movements of water, oscillating water columns that make use of wave induced air pressurization, overtopping devices that work like hydroelectric dams and wave surge converters that use horizontal motion of waves. The wave surge converters may be with flaps that protrude piercing the free surface or submerged and hinged at the bottom or top. The pitching motion of the flap can be used to drive hydraulic piston connected to electric generator. The geometry of this flap plays a vital role in conversion of the wave energy in to mechanical energy. Action of the wave on various flap geometry can be assessed by Computational Fluid Dynamics method and an optimum geometry that produces maximum mechanical power output can be derived. In this paper, different flap geometries made of same material and same volume are developed. Their performance under the wave conditions of a near shore point in Arabian sea (15’24’00” N, 73°45’58”E) is found out. The wave heights, wave periods, wave directions, surface current speed and directions, wind speed and directions for a year are collected. The best geometry is derived based on the power capturing capacity under these wave conditions by CFD methods.