<p>According to recent studies, global energy demand is projected to increase by approximately 1.8% in the future. As a result, the topic of energy harvesting, particularly wind energy harvesting, has received significant attention from researchers. In this research, a new dynamic model is proposed to determine the maximum vortex-induced vibration of a horizontally circular cylinder with a gap in a steady-state situation. The new dynamic model represents a nonlinear vibration system with a gap in the spring, damper, and horizontal cylinder system. The effect of the gap, as a significant parameter in cylinder vibration, was investigated, revealing an increase of 2.07 and 2.083 times in velocity and displacement, respectively. To analyze the fluid dynamics of the system, the lift force on the cylinder was obtained at a Reynolds number of 25,500, corresponding to the fully turbulent boundary layer vortex shedding regime. The dynamic modeling of the vibration system was conducted by extracting the equations of motion for the horizontal cylinder with a gap using Newton’s second law. The optimization results of the system show that considering optimal values in the locked-in and stable operating conditions leads to increased displacement and velocity of the vibrating cylinder with eccentricity compared to the system without eccentricity, resulting in a 4.31% increase in energy harvesting from the new cylinder system with gap compared to the system without gap. To validate the results of this research, the analytical results were compared with the findings of previous studies and the results obtained from ANSYS software, showing excellent agreement.</p>