A Novel Approach for Measuring the Energetic Characteristics of Drip-Type Rainfall Simulators

This paper presents the results of the characterization of a drip-type rainfall simulator, both in terms of rainfall kinetic power and momentum per unit time and area. The experimental tests for the measurements of the rainfall energetic characteristics were carried out in the laboratory of the Department of Agricultural, Food, and Forest Sciences of the University of Palermo, using a single capillary tube and coupling weighing and photographic methods to determine the equivalent diameter and the fall velocity of the simulated raindrops, respectively. Then, using literature fall velocity measures, a new relationship has been proposed to estimate the raindrop velocity as a function of its diameter and falling height. This relationship, positively tested using the laboratory measurements of the present investigation, allowed for easily determining the rainfall kinetic power and momentum of simulated rainfalls, once the raindrop falling height has been set and the equivalent diameter has been measured. Finally, to have a comprehensive characterization of drip-type rainfall simulators, operative instructions have been proposed.