Vibrational Characteristics of the LEP Vertical-Axis Wind Turbine Shaft for Various Solidity Ratios

Vertical-axis wind turbines are more advantageous than their horizontal-axis counterparts when placed in an array. They have the maximum capability to harvest the abundantly available source of wind energy. The presence of VAWT in the region of the onset of the atmospheric boundary layer, i.e. the earth's surface, and in offshore places where continuous unsteady airflow is encountered, has severe structural impacts in the form of vibrations that lead to system failure. To put a restraint on the problems caused, in this study, the leading-edge protuberance blades (LEP) are introduced on the VAWT instead of the previously available straight blades and are tested in the axial wind blower present in the Turbulence and Flow Control Laboratory at SASTRA Deemed University. It is to understand the diversification of the vibrational characteristics measured on the main shaft of the VAWT with the help of the triaxial accelerometer connected to a versatile data acquisition system. The results revealed that the LEP suppresses the evolution of the dynamic stall vortices considerably at low tip speed ratios, which in turn reduces the vibration on the turbine shaft, leading to the prevention of catastrophic failure of the system with the corresponding increase in turbine efficiency.