On the modeling of rain-wind induced vibrations of a simple oscillator

In this paper two model equations are presented for the study of rain-wind induced vibrations of a simple oscillator. As will be shown the presence of raindrops in a windfield may have an essential influence on the dynamic stability of the oscillator. In the first model equation the influence of the variation of the vibrating mass due to an incoming flow of raindrops hitting the oscillator and a mass flow which is blown and shaken off, is investigated. The time-varying vibrating mass is modeled by a piecewise constant and periodic function. In the second model equation the time-varying vibrating mass is modeled by a time harmonic function whereas simultaneously also time-varying lift and drag forces are considered.