Parametric study of an H-section oscillatory wind energy converter

Abstract

While flutter due to aerodynamic instability is a devastating phenomenon in airplanes and suspension bridges, taking advantage of flutter in converting wind and water energy into mechanical energy has been reported in the literature. In the present study, the oscillatory H-section wind energy converter developed by Ahmadi (1978)1978) was numerically modeled, and its performance was evaluated for various operational conditions. For this purpose, a coupled moving mesh CFD and dynamical motion simulation were conducted using the COMSOL software. To generate more realistic results, the oscillatory motion of the H-section was evaluated at each time instance using the net aerodynamic torque exerted on the turbine. The numerical results were validated against the experimental data for the static and dynamic conditions. Furthermore, the effects of several parameters, including the reduced frequency, damping ratio, Strouhal number, and shape factor, on the flow field pattern, as well as the turbine power coefficient, were determined. The simulation results showed that at a constant damping ratio, 43.9% and 17.3% enhancement in the maximum power coefficient was achieved by reducing the wind speed from 4.5 to 3 and 7.5 to 6 m/s, respectively. Moreover, a correlation was also presented based on the modification of the linearized theory for calculating the H-section energy converter power coefficient as a function of the affecting parameters. Furthermore, the optimum reduced frequency to maximize the power coefficient for various wind speeds was determined.