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

ABSTRACT

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.

KEYWORDS:

• rainfall simulator
• dynamic rainfall gauge system
• raindrop velocity
• raindrop kinetic energy
• rainfall uniformity
• experimental hydrology
• Christiansen uniformity coefficient

Editor R. Singh; Associate Editor (not assigned)

Editor R. Singh; Associate Editor (not assigned)

Acknowledgements

Jorge M. G. P. Isidoro acknowledges the financial support of the Portuguese Foundation of Science and Technology (FCT) to CIMA (Doi.org/10.54499/UIDB/00350/2020) through UIDB/00350/2020 and to the Associate Laboratory ARNET (Doi.org/10.54499/LA/P/0069/2020) through LA/P/0069/2020. The experiments were conducted at the Irrigation Laboratory of the Department of Water Resources at the Federal University of Lavras, Brazil.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) [Grant number APQ-00709-21], Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) [Grant numbers 429247/2018-4, 305295/2021-7] and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) [Grant number 001].