Characterization of artificial rainfall produced by a portable rainfall simulator using a rotating dynamic rainfall gauge system

Rainfall properties and drop spectra characterization is essential when designing and using rainfall simulators to properly replicate natural rainfall characteristics. This study considered a small-scale rainfall simulator operating under varying nozzle, pressure and rotating disc scenarios. A dynamic rainfall gauge system developed at the Federal University of Lavras was used to quantify the impact velocity of rainfall droplets and kinetic energy, and to conduct radial uniformity analyses. The results showed that the rainfall intensity, impact velocity of droplets, kinetic energy, and uniformity of distribution of rainfall are influenced by effects of the spray nozzle, operating pressure and the rotating disc opening of the rainfall simulator. Lower values of simulated rainfall kinetic energy were observed compared to the empirical natural rainfall kinetic energy at equivalent rainfall intensities. This paper highlights the influence of rainfall simulator design specifications on resultant rainfall spectra and validates simulated rainfall against empirically based natural rainfall characteristics.