Modeling the Vortex-Induced-Vibration of a Beam with Lock-In Phenomenon

Sustainable energy harvesting from environmental sources remains an active area of research, with vibration-based energy harvesters showing significant potential for supplying energy to low-power electronic devices in remote or hard-to-reach locations. One promising approach utilizes vortex-induced vibrations (VIV) in slender structures, where periodic vortex shedding from airflow generates mechanical oscillations that can be converted into electricity. Bladeless wind turbines, which operate on this principle, require accurate models to capture VIV dynamics, particularly when control mechanisms have to be implemented. However, conventional models often fail to account for the lock-in phenomenon, a critical effect in which the vortex shedding frequency synchronizes with the structure`s natural frequency over a range of wind speeds. This phenomenon has been well-documented through experimental studies and is essential for optimizing energy harvesting performance. This work reviews a model that simulates the dynamics of a typical bladeless turbine structure, consisting of a vertical cylinder anchored to the ground with an enveloping shell at its free end. The model simulates the lock-in phenomenon and explores the impact of structural stiffness on energy harvesting efficiency across different wind speeds.