Shape optimization of a blunt body Vibro-wind galloping oscillator

Abstract

The nonlinear dynamics of a transverse galloping blunt body oscillator is analyzed with respect to its geometric shape and size. The oscillator's equation of motion is studied using an approximation for the lateral aerodynamic force that is a polynomial function of the angle of attack. The harmonic balance method is used to solve the nonlinear differential equation of motion. This solution is used to determine the geometric parameters that minimize its critical wind speed for instability, increase its amplitude sensitivity to wind velocities beyond the critical speed, and minimize or eliminate amplitude hysteresis for increasing and decreasing wind speed. Optimum combinations of blunt body size and shape can be found that best satisfy these desired behaviors. These findings may be useful for creating a reliable, efficient wind energy harvesting system.