The development and commercialization of an efficient Oscillating Wave Energy Converter (OWEC) should be carried out with high attention to important parameters affecting its functionality in different environmental conditions. A common part of the analysis and design procedure is to find a balance between different goals. For an oscillatory part of an OWEC, a remarkable feature of the system and its efficiency is to move easily and rapidly which is directly related to the thorough understanding of the fluid-structure behaviour in different phases of the operation. This paper aims to provide the required theoretical and conceptual study by means of numerical simulation for developing, understanding, and improving the behaviour and functionality of a novel OWEC device. It is expected that the device can be adaptable and successful even for areas with less energetic waves. The primary shape of the moving part of the OWEC device is inspired by nature considering manufacturing possibility and the required symmetry for the device operation in the real sea. Then a numerical model is developed to investigate the hydrodynamic efficiency of the device for a specific site in the Caspian Sea. By tuning the dynamic characteristics, the maximum hydrodynamic efficiency and minimum energy implementation to the device are achieved. In each step of the optimization procedure, several sensitivity analyses and parametric studies have been conducted to reach a good understanding of the integrated control system and wave-structure interaction. This work will continue to provide all the required studies for the development of this OWEC concept.