In this study, the geometrical effect of circular cylinder with different sectors on energy harvesting of vortex induced vibration is investigated numerically. According to Von Karman vortex shedding phenomenon, the flow passes over a bluff body and as the results create vibration, can use this phenomenon with energy extraction and converting it into desired energy. In this paper, the focus was on discovering a cylinder geometry with more vibration than the base cylinder (circular cylinder); for this purpose, circular cylinder with different sectors, including ratio of 0.5, 0.6, 0.7, 0.8, 0.9, and 1 in two direction of arches frontal (AF) incoming flow and flat frontal (FF) incoming flow have been studied at Reynolds numbers of 100 and 200. Investigations have been carried out in the fluid and vibration field. In the fluid field, the aerodynamics forces are obtained on the cylinder with the help of computational fluid dynamics (CFD) and in the vibration field, by writing program in the Maple software, the displacement of the cylinder and, finally, recoverable potential power of the fluid were calculated. The results show that, at Reynolds numbers of 100 and 200, respectively, circular cylinder with and sectors in the placement direction of FF get the maximum extraction power of fluid and compared to the circular cylinder at Reynolds numbers of 100 and 200, respectively, 3.5 and 5.3 more times power harvesting. Also, in the same sectors cylinder, the cylinder with FF placement direction always has more power generation than the cylinder with AF placement direction.