The effect of drag force on the body frequencies and the power spectrum of a bladeless wind turbine

Abstract

New types of bladeless wind turbines and electricity generation are currently one of the most interesting topics in engineering. Electricity generation using structural vibration due to the resonance phenomenon is the concept behind a vortex bladeless turbine. The present study numerically investigated the effects of the drag force on the body frequency of an oscillating bladeless wind turbine. A two-dimensional numerical simulation was performed for a cylinder with a semi-circular cross-flow cross-section in two different cases. This research was conducted for both uncontrolled and controlled oscillating cylinders. The controlling process was performed using a pair of ring magnets as springs with a variable coefficient. The flow field, vibration, vortex shedding, structural frequencies, and resonance phenomena were studied in this research. Finally, the controlled and uncontrolled frequencies of the cylinder are explored, and the power spectra for various velocities are analyzed in two different states, namely, with and without a tuning system. From the results, it can be concluded that the usage of the controlling system in these turbines can significantly regulate the oscillations and increase the frequency value by limiting the vibration amplitude. According to this principle, it can be inferred that increasing the frequency of fluctuations greatly increases the production capacity of these turbines.