Quenching of Self-Excited Vibrations and Generation of Electricity by Using Hula-Hoop.

This paper deals with the quenching problem of self-excited vibrations by using a device composed of a Hula-Hoop and a generator. This device is also additionally able to generate electricity. The Runge-Kutta-Gill method is applied to the numerical analysis of a Rayleigh's type self-excited system with the device. The solutions obtained are divided into two main categories ; periodic solutions and chaos accompanied by Hula-Hoop's vibration and rotation. An optimum approach for quenching the self-excited vibration was discussed. As a result, it was clarified that for the optimum design of the device there existed a certain relation among the moment of inertia, the mass of Hula-Hoop and the capacity of generator, and the vibration at that time was chaos as in the impact damper which we analyzed before. The condition of maximum generation of electricity was not equal to that of minimum vibration amplitude of the self-excited system. An experiment was performed to quench vortex-induced vibration and to generate electricity by using the device. The experimental results agreed well qualitatively with those from the numerical computational analysis.